Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 48

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang Jan 2008

Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang

Retrospective Theses and Dissertations

Because of its appealing simplicity, the elastic network model (ENM) has been widely accepted and applied to study many molecular motion problems, such as the molecular mechanisms of chaperonin GroEL-GroES function, allosteric changes in hemoglobin, ribosome motions, motor-protein motions, and conformational changes in general. In this dissertation, the ENM is employed to study various protein dynamics problems, and its validity is also examined by comparing with experimental data. First, we apply principal component analysis (PCA) to identify the essential protein motions from multiple structures (X-ray, NMR and MD) of the HIV-1 protease. We find significant similarities between the first few ...


Studies Of Intermediates And Regulation In Snare-Mediated Membrane Fusion, Xiaobing Lu Jan 2008

Studies Of Intermediates And Regulation In Snare-Mediated Membrane Fusion, Xiaobing Lu

Retrospective Theses and Dissertations

At the synapse, neurotransmitters are released via Ca2+-triggered exocytotic fusion of synaptic vesicles with the presynaptic plasma membrane. The whole process is controlled by various proteins. SNAREs have been recognized as the key components that drive membrane fusion. In addition, many other proteins, such as Munc18/nSec1, Mun13, synaptotagmin, complexin, etc. are characterized to regulate synaptic transmission temporally and spatially.;The in vitro bulk fluorescence assay was applied to examine the kinetics of membrane fusion of liposomes mediated by recombinant neuronal SNAREs and led to the demonstration of hemifusion as an intermediate in the pathway. In order to monitor ...


Biophysical Characterization Of The 117 Amino Acids Long N-Terminal Segment Of D-Raf (Isoform A), Oren Tchaicheeyan Jan 2007

Biophysical Characterization Of The 117 Amino Acids Long N-Terminal Segment Of D-Raf (Isoform A), Oren Tchaicheeyan

Retrospective Theses and Dissertations

Drosophila Raf (D-Raf) is an orthologue of Human B-Raf. D-Raf may have two splice variants, a short (Isoform A, I-A) and a long one (Isoform B, I-B). Protocols for over-expression (E. Coli) and purification of 117 amino acids (aa) N-terminal segment (NTS) of D-Raf protein (I-A), both WT and Mutant (T60E) were established. These protein constructs were also biophysically characterized. Thrombin cleavage conditions were optimized, as monitored by 5 amino acid NTS sequencing, mass spectroscopy and SDS-PAGE electrophoresis. An attempt to purify the 160 aa D-Raf (I-B) NTS failed. NMR characterization in a 700 MHz magnet employing three experiments (HSQC ...


Determinants Of Substrate Recognition And Mechanisms Of Subunit Exchange, Yang Zhou Jan 2007

Determinants Of Substrate Recognition And Mechanisms Of Subunit Exchange, Yang Zhou

Retrospective Theses and Dissertations

Adenylosuccinate synthetase (ADSS) offers a good opportunity to measure the effect of non-bonded interactions. Both IMP and 2'-deoxy-IMP are good substrates supporting identical binding affinities and maximal velocities; however, L-aspartate exhibits significant differences in binding affinities depending on which nucleotide is used as a substrate. Crystal structures of both complexes were identical except for the absence of the 2'-OH group in the dexoy-nucleotide complex. The decrease in energy (∼2 kcal/mole) in non-bonded interactions due to the loss of one atom explains the nearly 40-fold difference in the binding affinity of L-aspartate and an analog of L-aspartate called ...


Structural And Functional Studies On Membrane Fusion Proteins-Snares, Yibin Xu Jan 2007

Structural And Functional Studies On Membrane Fusion Proteins-Snares, Yibin Xu

Retrospective Theses and Dissertations

Membrane fusion is a ubiquitous and essential intracellular function. Membrane fusion is mediated by a protein superfamily known as N-ethymaleimide-sensitive fusion protein attachment protein receptors (SNAREs). From plant to mammal, there is a remarkable sequence similarity among the SNARE-family related to the conserved function of this family. The function of SNAREs has been proposed to be the key to membrane fusion as minimal fusion machinery. Depending on their distinct membrane distribution, SNAREs were classified into v (vesicle)-SNAREs and t (target)-SNAREs. It is widely believed that SNARE complex assembly by v- and t-SNAREs on opposite membranes offers the ultimate ...


Crystallographic Analysis Of Parasponia Andersonii Hemoglobin, Andrea Savage Jan 2007

Crystallographic Analysis Of Parasponia Andersonii Hemoglobin, Andrea Savage

Retrospective Theses and Dissertations

The x-ray crystal structure of ferric Parasponia andersonii hemoglobin has been determined to 2.3 A resolution by molecular replacement with Rice hemoglobin 1 (rHb1). By means of absorbance spectroscopy, electrochemistry and x-ray crystallography, it has been revealed that depending on the oxidation state, the heme iron can exsist in either the pentacoordinate or hexacoordinate form. Pentacoordination of the heme iron is found primarily in the deoxy ferrous (2+) form, whereas the ferric (3+) form is exhibited predominantly in bis-histidine coordination. This is unique among known forms of hemoglobins. Furthermore, the crystallographic data has provided evidence which supports previous works ...


Role Of Leu[Superscript B 10] In Cytoglobin And Comparison Of Direct And Indirect Measurements Of Hexacoordinate Hemoglobin Ligand Affinity, Jordan Richard Witmer Jan 2007

Role Of Leu[Superscript B 10] In Cytoglobin And Comparison Of Direct And Indirect Measurements Of Hexacoordinate Hemoglobin Ligand Affinity, Jordan Richard Witmer

Retrospective Theses and Dissertations

Hexacoordinate hemoglobins (HxHbs) have recently been discovered and have been found in nearly all living organisms. In humans, hxHbs are represented by neuroglobin (Ngb) and cytoglobin (Cgb). While Ngb is principally found in the brain, Cgb is ubiquitously expressed in all tissues. Ligand binding in hexacoordinate hemoglobins is complex due to the reversible coordination of the heme iron by the distal histidine. Hexacoordination regulates ligand binding and is regulated by specific residues in the heme pocket including the B10 position. Therefore, we investigated the influence of LeuB10 on hexacoordination and ligand binding in Cgb. Ligand binding was analyzed for recombinant ...


The Role Of Tyr61 In Synechocystis Hemoglobin In Regulating E-Helix Movement, Anand Venugopal Jan 2007

The Role Of Tyr61 In Synechocystis Hemoglobin In Regulating E-Helix Movement, Anand Venugopal

Retrospective Theses and Dissertations

Hexacoordinate hemoglobins have been discovered that have yet to have a functional role confidently assigned to them. The eubacteria synechocystis sp. PCC 6803 has been found to have a truncated hemoglobin which is hexacoordinated. The structures of the hexacoordinated and cyanide bound forms of synechocystis hemoglobin have been solved, and a large shift in the E-helix has been seen upon ligand binding. Also, the loop connecting the E and F helix contains residues Tyr61 and Asp62 that are involved in hydrogen bonding networks in the cyanide-bound and hexacoordinate states respectively. A mutation was made to the Y61 residue to make ...


Biophysical And Biochemical Characterization Of Hexacoordinate Hemoglobins, Benoit Joel Smagghe Jan 2007

Biophysical And Biochemical Characterization Of Hexacoordinate Hemoglobins, Benoit Joel Smagghe

Retrospective Theses and Dissertations

Within the hemoglobin (Hb) superfamily, an unusual group called hexacoordinate hemoglobin (hxHbs) whose members are found in all living organisms is the subject of exciting studies since their discovery. They are named "hexacoordinate" because of reversible coordination of the sixth coordination site of the heme iron by a histidine side chain located in the heme distal pocket. Interestingly, hxHbs share high degree of similarity in their primary sequence and a common globin fold indicating that they might share a common role and that endogenous coordination might be an important part of their not yet characterized physiological function. The characterization of ...


A Penalty Function Method For Constrained Molecular Dynamics , Ajith Gunaratne Jan 2006

A Penalty Function Method For Constrained Molecular Dynamics , Ajith Gunaratne

Retrospective Theses and Dissertations

We propose a penalty-function method for constrained molecular dynamic simulation by defining a quadratic penalty function for the constraints. The simulation with such a method can be done by using a conventional, unconstrained solver only with the penalty parameter increased in an appropriate manner as the simulation proceeds. More specifically, we scale the constraints with their force constants when forming the penalty terms. The resulting force function can then be viewed as a smooth continuation of the original force field as the penalty parameter increases. The penalty function method is easy to implement and costs less than a Lagrange multiplier ...


Studies Of Intermediates In Snare-Induced Membrane Fusion , Fan Zhang Jan 2006

Studies Of Intermediates In Snare-Induced Membrane Fusion , Fan Zhang

Retrospective Theses and Dissertations

The purpose of this course of study is to understand the intermediates during SNAREs assembly and the membrane fusion mediated by SNAREs. SNAREs have been proposed to be the minimal machinery for the membrane fusion. According to the location distribution, SNAREs can be classified as either v-(vesicles) or t-(target) SNAREs. The assembly of three SNARE components from the opposing membranes into the ternary complex is believed to provide the ultimate driving force for merging the separate bilayers into a continuous entity. Before this step the t-SNAREs associate as the binary complex on the target membrane to serve as ...


Structural And Functional Studies On Snares-Mediated Membrane Fusion , Yong Chen Jan 2006

Structural And Functional Studies On Snares-Mediated Membrane Fusion , Yong Chen

Retrospective Theses and Dissertations

Membrane fusion is an essential biological process for vesicle trafficking in eukaryotic cells. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are a family of proteins that have been recognized as key components of protein complexes that drive membrane fusion. The SNARE proteins localized in opposite membranes form a SNARE complex, which bridges the two membranes into close proximity and promotes fusion. Despite considerable sequence divergence among SNARE proteins, this fusion machinery is conserved structurally, mechanistically and evolutionally from yeast to human;Site-directed spin labeling (SDSL) and electron paramagnetic resonance (EPR) are well established techniques to study the structures of membrane ...


An Examination Of Hexacoordinate Hemoglobins Using The Techniques Of Biochemistry, Biophysics And Molecular Biology , James Thomas Trent Iii Jan 2006

An Examination Of Hexacoordinate Hemoglobins Using The Techniques Of Biochemistry, Biophysics And Molecular Biology , James Thomas Trent Iii

Retrospective Theses and Dissertations

Hexacoordinate hemoglobins are found in a truly diverse array of organisms, ranging from cyanobacteria to humans. The prevalence of these proteins in nature coupled with very high sequence identity between species homologues suggests they have a role vital to life. The high sequence identity also implies that hxHb structural features, including the hexacoordination phenomenon, are critical aspects of the physiological function. A detailed understanding of the ligand binding behavior of these proteins will not only facilitate efforts towards discovering their physiological role(s), but will also help explain how hxHbs perform their function. This dissertation consists of four published papers ...


Structural Characterization Of Ligand Binding In Hexacoordinate Hemoglobins , Julie Anne Hoy Jan 2006

Structural Characterization Of Ligand Binding In Hexacoordinate Hemoglobins , Julie Anne Hoy

Retrospective Theses and Dissertations

Hemoglobins are ancient proteins that predate the divergence of prokaryotes and eukaryotes. Although the most thoroughly studied hemoglobins are mammalian oxygen transporters, it has become clear that this function is a recent evolutionary advancement coinciding with the "oxygen revolution" and the development of multicellular organisms. Hemoglobins capable of oxygen transport are highly specialized structurally to maintain pentacoordination of the heme and appropriate ligand rate and equilibrium constants, while preventing autooxidation due to bound oxygen. Their predecessors however, adopt a more energetically favorable hexacoordinate conformation that precludes oxygen transport;Despite the fact that hexacoordinate hemoglobins are ubiquitous in biological organisms, little ...


Distance-Based Nmr Structure Determination And Refinement, Feng Cui Jan 2005

Distance-Based Nmr Structure Determination And Refinement, Feng Cui

Retrospective Theses and Dissertations

Protein structures play a pivotal role in understanding protein functions. X-ray crystallography and nuclear magnetic resonance spectroscopy (NMR) are two main experimental approaches for protein structure determination. The structures determined by NMR are not as accurate as those by X-ray crystallography in general, due to limited distance data (e.g. NOEs) that can be generated from NMR experiments. The NMR modeling algorithms are not well developed either, to produce high-quality structures with desired accuracy and efficiency. To address the NMR modeling issues, a so-called geometric build-up approach for NMR modeling has been developed, which remarkably reduces computing time in determining ...


A Threading Approach To Protein Structure Prediction: Studies On Tnf-Like Molecules, Rev Proteins, And Protein Kinases , Yungok Ihm Jan 2004

A Threading Approach To Protein Structure Prediction: Studies On Tnf-Like Molecules, Rev Proteins, And Protein Kinases , Yungok Ihm

Retrospective Theses and Dissertations

The main focus of this dissertation is the application of the threading approach to specific biological problems. The threading scheme developed in our group targets incorporating important structural features necessary for detecting structural similarity between the target sequence and the template structure. This enables us to use our threading method to solve problems for which sequence-based methods are not very much useful. We applied our threading method to predict the three-dimensional structures of lentivirus (EIAV, HIV-1, FIV, SIV) Rev proteins. Predicted structures of Rev proteins suggest that they share a structural similarity among themselves (four-helix bundle). Also, the threading approach ...


Nonphotochemical Hole-Burning Imaging Studies Of In Vitro Carcinoma And Normal Cells Utilizing A Mitochondrial Specific Dye , Richard Joseph Walsh Jan 2002

Nonphotochemical Hole-Burning Imaging Studies Of In Vitro Carcinoma And Normal Cells Utilizing A Mitochondrial Specific Dye , Richard Joseph Walsh

Retrospective Theses and Dissertations

Low temperature Nonphotochemical Hole Burning (NPHB) Spectroscopy of the dye rhodamine 800 (MF680) was applied for the purpose of discerning differences between cultured normal and carcinoma ovarian surface epithelial (OSE) cells. Both the cell lines were developed and characterized at the Mayo Clinic (Rochester, MN), with the normal cell line having been transfected with a strain of temperature sensitive Simian Virus 40 Large T Antigen (SV40) for the purpose of extending the life of the cell culture without inducing permanent changes in the characteristics of the cell line. The cationic lipophilic fluorophore rhodamine 800 preferentially locates in in situ mitochondria ...


Proline Cis/Trans Isomerization Regulates A T Cell Specific Tyrosine Kinase , Kristine Nicole Brazin Jan 2002

Proline Cis/Trans Isomerization Regulates A T Cell Specific Tyrosine Kinase , Kristine Nicole Brazin

Retrospective Theses and Dissertations

This dissertation examines the role of protein-protein interactions that regulate the conformation and function of the Tec family kinase, interleukin-2 tyrosine kinase (Itk). Tec family kinases are expressed in hematopoetic cells and modulate intracellular signaling cascades in response to external stimuli. The domain structure of Tec family members contains the conserved SH3, SH2, and catalytic domains common to many kinase families, yet they are distinguishable by the presence of a unique N-terminal sequence. The mechanism by which Itk is regulated is not well understood. Both nuclear magnetic resonance spectroscopy and functional assays were used to elucidate a novel regulatory mechanism ...


Photophysics And Light Induced Photobiology Of Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Jaehun Park Jan 2001

Photophysics And Light Induced Photobiology Of Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Jaehun Park

Retrospective Theses and Dissertations

The dissertation mainly focuses on the excited-state photophysics and the light-induced biological activity of hypericin and its analogs.;Femtosecond laser technology has provided the opportunity to investigate the rapid dynamics of these molecules. Fluorescence upconversion measurements, which monitor only emission from the fluorescent singlet state, demonstrate that hexamethoxy hypericin, which possesses no labile protons, has an instantaneous rise time for its transient response. On the other hand, hypericin shows a clear 10-ps rise time. This confirms excited-state H-atom transfer as the primary photophysical process in hypericin.;Femtosecond transient absorption spectroscopy technique is used to determine if excited state H-atom transfer ...


Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu Jan 2001

Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu

Retrospective Theses and Dissertations

Photosystem I, one of the two light driven reaction centers of oxygenic photosynthesis, functions as the light-driven plastocyanin-ferredoxin oxidoreductase in the thylakoid membranes of cyanobacteria and chloroplasts. It is a pigment protein complex with 11--14 proteins and several types of organic (e.g. chlorophyll a) and inorganic energy and electron transfer cofactors (e.g. Fe-S cluster). The objectives of this dissertation are: (i) to demonstrate that the spectroscopic and kinetic properties of photosystem I cofactors are determined by the protein environments, (ii) to determine whether the electron transfer in photosystem I is unidirectional or bidirectional, (iii) to identify which aromatic ...


X-Ray Crystallographic Studies Of The Metal Binding Sites On Recombinant Porcine Fructose-1,6-Bisphosphatase , Jun-Yong Choe Jan 2001

X-Ray Crystallographic Studies Of The Metal Binding Sites On Recombinant Porcine Fructose-1,6-Bisphosphatase , Jun-Yong Choe

Retrospective Theses and Dissertations

Fructose 1,6-bisphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11, FBPase; Fructose 1,6-bisphosphate + H2O ⇔ Fructose 6-phosphate + Phosphate) is a key regulatory enzyme in gluconeogenesis. It is a homotetramer with subunit molecular mass of 37 kDa. There are two different quaternary conformations of FBPase: the R-state (the active conformation) and the T-state (the inactive conformation). FBPase is inhibited allosterically by AMP. FBPase requires divalent metal ions (Mg2+, Mn 2+, Zn2+, or Co2+) to hydrolyze fructose 1,6-bisphosphate. Some monovalent cations (K+, Rb+, Tl+ or NH3+) maximize the enzyme activity, whereas lithium ions inhibit the enzyme. Li+ inhibition of FBPase ...


Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov Jan 1999

Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov

Retrospective Theses and Dissertations

The dissertation focuses on the ultrafast primary photoprocesses of the title anti-viral and anti-cancer agents, whose activity depends on light which is also accompanied by photoacidification in vesicles and living cells;By complementing the techniques of time-resolved absorption spectroscopy with those of fluorescence upconversion and applying them to hypericin, hypocrellin A and B, and their methylated analogs that are unable to execute proton transfer, it was demonstrated that intramolecular excited-state hydrogen atom transfer is a dominant primary nonradiative process;For hypocrellin A in viscous solvents such as octanol and ethylene glycol, an absorption transient of ∼10-ps duration, similar to the ...


Application Of Spectral Hole Burning To The Study Of In Vitro Cellular Systems , Nebojsa Milanovich Jan 1999

Application Of Spectral Hole Burning To The Study Of In Vitro Cellular Systems , Nebojsa Milanovich

Retrospective Theses and Dissertations

The high resolution spectroscopic technique of nonphotochemical hole burning (NPHB) was applied to the study of in vitro cellular systems. Suspensions of two well-characterized cell lines were used for these studies: (1) MCF-10F cells, a normal human breast epithelial cell line, and (2) MCF-7 cells, a human breast adenocarcinoma cell line. Both cell lines were stained with the dye aluminum phthalocyanine tetrasulfonate (APT) and prepared for spectroscopic study at liquid helium temperatures. Routinely measured hole burning parameters were obtained for the two cell types and compared in order to differentiate between physical properties of normal and cancer cells;A comparison ...


Hole Burning With Pressure And Electric Field: A Window On The Electronic Structure And Energy Transfer Dynamics Of Bacterial Antenna Complexes , Hsing-Mei Wu Jan 1998

Hole Burning With Pressure And Electric Field: A Window On The Electronic Structure And Energy Transfer Dynamics Of Bacterial Antenna Complexes , Hsing-Mei Wu

Retrospective Theses and Dissertations

Light-harvesting complexes of cyclic symmetry from purple bacteria are studied using absorption and high pressure- and Stark-hole burning spectroscopies. The B800→B850 energy transfer rate of (~2 ps)-1 determined by hole burning and pump-probe spectroscopies is weakly dependent on B800-B850 energy gap varied by pressure and temperature. This resilience is explained in terms of a modified Forster theory with the spectral overlap provided by the B800 fluorescence origin band and weak vibronic absorption of B850. Explanations for the additional sub-picosecond relaxation channel of B800 with excitation on the blue side are given. Pressure and temperature dependent studies show that ...


Biophysical Studies Of Catalytic And Starch Binding Domains Of Wild-Type And Mutant Glucoamylases From Aspergillus Awamori , Saber Malek Abdullah Khan Jan 1998

Biophysical Studies Of Catalytic And Starch Binding Domains Of Wild-Type And Mutant Glucoamylases From Aspergillus Awamori , Saber Malek Abdullah Khan

Retrospective Theses and Dissertations

Aspergillus awamori catalytic and starch binding domains were prepared, purified and characterized. Sedimentation equilibrium experiments and MALDI-TOF spectra reveals that GA470 and SBD contains ~12% and 5% carbohydrate, respectively. Temperature denaturation experiments indicate that catalytic domain unfolds irreversibly whereas that of SBD is reversible with DeltaH of ~410 and 71 kcal/mol, respectively, and T m of 60.9° and 51.3°C, respectively. Analysis of scan rate dependency data suggest that the thermal unfolding of GA470 was partially under kinetic control and do not follow a single two-step model. Comparison of Tm of isolated and intact GA470 and SBD ...


Molecular Analysis Of A Shaker-Related K+ Channel In Leech , Jamie Lynn Weiss Jan 1996

Molecular Analysis Of A Shaker-Related K+ Channel In Leech , Jamie Lynn Weiss

Retrospective Theses and Dissertations

Voltage-gated K+ channels play a critical role in regulating the excitability of neurons and muscle. In the nervous system of many species voltage-gated K+ channels are primarily represented by four subfamilies, Shaker, Shal, Shab, and Shaw. We have cloned a K+ channel in the leech Haemopis marmorata, called LK-1, using a PCR based screen that was designed to isolate any of the four defined subfamilies of voltage-gated K+ channels. LK-1 primary amino acid sequence reveals that it is a Shaker-related channel sharing the highest amino acid identity within the transmembrane domains (48-58%) to classified Shaker homologs in species both higher ...


X-Ray Crystallographic Studies Of The Nucleotide Binding Sites On Adenylosuccinate Synthetase From Esherichia Coli , Bradley Wayne Poland Jan 1996

X-Ray Crystallographic Studies Of The Nucleotide Binding Sites On Adenylosuccinate Synthetase From Esherichia Coli , Bradley Wayne Poland

Retrospective Theses and Dissertations

The crystal structures of unligated adenylosuccinate synthetase from Esherichia coli in the space groups P21 and P212121 have been refined to R-factors of 0.199 and 0.206 against 2.0 and 2.5A data, respectively. The dominant structural motif of the synthetase monomer is a central 10 stranded [beta]-sheet composed of 9 parallel strands and a 10th antiparallel strand. Four subdomains extend off of this [beta]-sheet and contribute loops of residues which are disordered. The dimer interface involves two nearly-independent regions. A pair of helicea (H4 & H5) interacting with their symmetry equivalent mates defines the first region. The second region involves structural elements which connect strands of the central [beta]-sheet. Residues in the putative IMP binding site are also located at or near the dimer interface;The P212121 crystal form allows gradual infusion of guanosine triphosphate ribonucleotides ...


Photophysics And Activity Of Biological Systems Containing The Optical Probes 7-Azatryptophan And Its Analogs , Rebecca Lynne Rich Jan 1995

Photophysics And Activity Of Biological Systems Containing The Optical Probes 7-Azatryptophan And Its Analogs , Rebecca Lynne Rich

Retrospective Theses and Dissertations

A major use of photophysical apparatus is the study of biological systems, for example, peptides, proteins, and DNA, that contain one or more chromophores. In recent years the incorporation of nonnatural fluorescent compounds into these systems has gained great popularity. A number of optical 'tags' have been suggested as detection tools of structure and function; we propose the use of the tryptophan derivative, 7-azatryptophan, as an intrinsic probe in photophysical analyses of proteins. Not only is this chromophore spectroscopically distinct from tryptophan and all other natural amino acids, but we have demonstrated the successful incorporation of 7-azatryptophan into peptide sequences ...


Spectral Hole Burning Studies Of Photosystem Ii , Hai-Chou Chang Jan 1995

Spectral Hole Burning Studies Of Photosystem Ii , Hai-Chou Chang

Retrospective Theses and Dissertations

Low temperature absorption and hole burning spectroscopies were applied to the D1-D2-cyt b[subscript]559, and the CP47 and CP43 antenna protein complexes of Photosystem II from higher plants. Low temperature transient and persistent hole-burning data and theoretical calculations on the kinetics and temperature dependence of the P680 hole profile are presented and provide convincing support for the linker model. Implicit in the linker model is that the 684-nm-absorbing Chl a serve to shuttle energy from the proximal antenna complex to reaction center. The stoichiometry of isolated Photosystem II Reaction Center (PSII RC) in several different preparations is also discussed ...


Monolayer Studies Of Novel Synthetic Compounds And Biological Systems , Jingyuan Wang Jan 1994

Monolayer Studies Of Novel Synthetic Compounds And Biological Systems , Jingyuan Wang

Retrospective Theses and Dissertations

A general review on preparation and methods of characterization of monolayers was given in Chapter 1. Different projects were undertaken in the research of this dissertation. Neutron and X-ray reflection studies of fullerene C[subscript]60 and its derivative monolayers were performed in Chapter 1. Neutron and X-ray reflection measurements and surface pressure isotherms of spread films of C[subscript]60-dodecylamine adduct C[subscript]60-(NH[subscript]2(CH[subscript]2)[subscript]11CH[subscript]3][subscript]x and C[subscript]60-propylamine adduct C[subscript]60-(NH[subscript]2C[subscript]3H[subscript]7][subscript]x indicate that these C[subscript]60 ...