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Full-Text Articles in Life Sciences

Layer-By-Layer Self -Assembly For Enzyme And Dna Encapsulation And Delivery, Amish Patel Oct 2004

Layer-By-Layer Self -Assembly For Enzyme And Dna Encapsulation And Delivery, Amish Patel

Doctoral Dissertations

Thin wall microcapsules were formed via Layer-by-Layer Self-Assembly of alternate adsorption of oppositely charged polyelectrolyte on microcores. After the core dissolution, empty polymeric shells with 20–25 nm thick walls were obtained. These microcapsules were loaded with Myoglobin, Hemoglobin and Glucose Oxidase by opening capsule pores at low pH and closing them at higher pH. The native structure of the enzyme was not affected due to different treatments. Biocompatible nanoshells were also prepared for encasing DNA. Using the same Layer-by-Layer Self-Assembly approach nanoparticle were constructed containing DNA as one of the layers. The nanoparticles of different architecture were used to ...


The Importance Of A Critical Protonation State And The Fate Of The Catalytic Steps In Class A Β-Lactamases And Penicillin-Binding Proteins, Dasantila Golemi-Kotra, Samy O. Meroueh, Choonkeun Kim, Sergei B. Vakulenko, Alexey Bulychev, Ann J. Stemmler, Timothy L. Stemmler, Shahriar Mobashery May 2004

The Importance Of A Critical Protonation State And The Fate Of The Catalytic Steps In Class A Β-Lactamases And Penicillin-Binding Proteins, Dasantila Golemi-Kotra, Samy O. Meroueh, Choonkeun Kim, Sergei B. Vakulenko, Alexey Bulychev, Ann J. Stemmler, Timothy L. Stemmler, Shahriar Mobashery

Biochemistry and Molecular Biology Faculty Publications

b-Lactamases and penicillin-binding proteins are bacterial enzymes involved in antibiotic resistance to b-lactam antibiotics and biosynthetic assembly of cell wall, respectively. Members of these large families of enzymes all experience acylation by their respective substrates at an active-site serine as the first step in their catalytic activities. A Ser-X-X-Lys sequence motif is seen in all these proteins and crystal structures demonstrate that the side chain functions of the serine and lysine are in contact with one another. Three independent methods were used in this report to address the question of the protonation state of this important lysine (Lys73) in the ...


Core Concepts In Biochemistry And Molecular Biology In An Integrated Mbbs Curriculum, M P. Iqbal Apr 2004

Core Concepts In Biochemistry And Molecular Biology In An Integrated Mbbs Curriculum, M P. Iqbal

Department of Biological & Biomedical Sciences

No abstract provided.


Molecular And Functional Analysis Of Drosophila Hillarin And Its Leech Homolog , Yun Ji Jan 2004

Molecular And Functional Analysis Of Drosophila Hillarin And Its Leech Homolog , Yun Ji

Retrospective Theses and Dissertations

This thesis describes the molecular and functional analysis of the leech Hillarin and its Drosophila homolog D-hil. Leech Hillarin was identified by screening a leech expression library with the mAb Lan3-15, which specifically labels the axon hillock region of leech neurons. Database searches revealed that leech Hillarin has a number of potential homologs in a variety of organisms such as yeast, cyanobacterium, fly, nematode, mouse and human and that these proteins share two novel protein domains, the W180 domain and the H domain. The W180 domain is enriched with tryptophans whereas the H domain shares high number of invariant residues ...


Site-Directed Mutagenesis In Photosystem I Complex: Functional Analysis Of P700 , Maria Pantelidou Jan 2004

Site-Directed Mutagenesis In Photosystem I Complex: Functional Analysis Of P700 , Maria Pantelidou

Retrospective Theses and Dissertations

Photosynthesis is the process by which plants and cyanobacteria convert light to chemical energy. Photosystem I and photosystem II are the two photosynthetic reaction centers that perform light-driven electron transport across thylakoid membranes. Using photon energy, photosystem I oxidizes plastocyanin, transfers the electron through a series of cofactors, and finally reduces ferredoxin. Photosystem I, consists of 12 or more proteins, 96 chlorophyll alpha molecules, 22 beta-carotenes, two phylloquinones, two lipid molecules, and three iron-sulfur clusters. PsaA and PsaB, the largest subunits, surround the electron transfer chain cofactors with a two-fold symmetry. These cofactors are: P700, the primary electron donor chlorophylls ...


Assembly Of The 30s Ribosomal Subunit: S15 As The Probe , Indumathi Jagannathan Jan 2004

Assembly Of The 30s Ribosomal Subunit: S15 As The Probe , Indumathi Jagannathan

Retrospective Theses and Dissertations

The aim of this study is to dissect molecular events that occur during the assembly of 30S subunit of the E. coli ribosome. The 30S ribosomal subunit is made up of 16S ribosomal RNA (rRNA) and 21 proteins (S1--S21). Crystal structure of the 30S subunit has answered longstanding questions on the three-dimensional organization of its constituents. However, this view does not expose the nature of interesting cooperative movements and conformational changes that occur during the formation of this macromolecular complex. Hence, biochemical and genetic efforts are required to understand these rearrangements.;In this study, we have employed directed hydroxyl radical ...


Insights Into The Working Of P-Rex2: An Inositol Polyphosphate 4-Phosphatase Domain Containing Guanine Nucleotide Exchange Factor , Raji Elizabeth Joseph Jan 2004

Insights Into The Working Of P-Rex2: An Inositol Polyphosphate 4-Phosphatase Domain Containing Guanine Nucleotide Exchange Factor , Raji Elizabeth Joseph

Retrospective Theses and Dissertations

Inositol polyphosphate 4-phosphatases (IP4Ps) are enzymes that catalyze the hydrolysis of the 4-position phosphate of phosphatidylinositol 3,4-bisphosphate to form phosphatidylinositol 3-phosphate. Database searches for proteins similar to IP4Ps led to the identification of two novel proteins: P-Rex1 and P-Rex2. These proteins, in addition to sharing similarity with IP4Ps, had a Dbl homology (DH) domain followed by a pleckstrin homology (PH) domain, a characteristic feature of the Dbl family of guanine nucleotide exchange factors (GEFs). P-Rex1 was recently isolated from neutrophils, where it plays a key role in stimulating the neutrophil oxidative burst by activating Rac, a component of the ...


Functional Interactions Among Starch Biosynthetic Enzymes , Seungtaek Kim Jan 2004

Functional Interactions Among Starch Biosynthetic Enzymes , Seungtaek Kim

Retrospective Theses and Dissertations

Understanding the starch biosynthetic mechanism is often hampered by the existence of many isoforms of the involved enzymes as well as numerous pleiotropic effects of mutations affecting these enzymes. This dissertation investigated interactions among starch biosynthetic enzymes, focusing on both physical association of the proteins and functional interactions in a transgenic in vivo system. Specific protein-protein interactions among the starch biosynthetic enzymes that were indicated by yeast two-hybrid experiments were confirmed directly by affinity chromatography. The functional significance of such interactions, specifically between starch synthase and starch branching enzyme, was studied using heterologous expression in the yeast Saccharomyces cerevisiae. A ...


Structural And Molecular Analysis Of Leech Neuronal Proteins, Calsensin And Filamin , Deepa V. Venkitaramani Jan 2004

Structural And Molecular Analysis Of Leech Neuronal Proteins, Calsensin And Filamin , Deepa V. Venkitaramani

Retrospective Theses and Dissertations

This thesis describes the structural and molecular analysis of two leech neuronal proteins, Calsensin and Filamin. Calsensin is an EF-hand calcium-binding protein expressed by a subset of peripheral sensory neurons which fasciculate into a single tract in the leech central nervous system. Calsensin is a 9 kD protein with two EF-hand calcium-binding motifs. Calsensin can multimerize via disulfide bridge formation involving the two cysteine residues in vitro. Furthermore, Calsensin shows differential gel migration depending on the presence or absence of calcium suggesting a conformational change upon calcium binding. Using multidimensional NMR spectroscopy we have determined the solution structure and backbone ...


The Essential Jil-1 Kinase Regulates Histone H3 Phosphorylation And Maintains Chromatin Structure In Drosophila , Weiguo Zhang Jan 2004

The Essential Jil-1 Kinase Regulates Histone H3 Phosphorylation And Maintains Chromatin Structure In Drosophila , Weiguo Zhang

Retrospective Theses and Dissertations

JIL-1 encodes a chromatin-associated tandem serine/threonine kinase in Drosophila melanogaster. JIL-1 predominantly associates with interbands on polytene chromosomes. It appears at higher levels on the X chromosome than on autosomes in males, and distributes about equally on all chromosomes in females. In addition, in males JIL-1 overlaps with the MSL (for male specific lethal) complex that specifically associates with the male X chromosome on which expression of most genes are upregulated.;We isolated JIL-1 mutants by inducing imprecise excision of an EP element inserted in JIL-1. We found that JIL-1 is required for viability of both females and males ...


Structural And Biochemical Insight Into The Inositol Polyphosphate 4-Phosphatase Family Of Proteins , Colin Tucker Shearn Jan 2004

Structural And Biochemical Insight Into The Inositol Polyphosphate 4-Phosphatase Family Of Proteins , Colin Tucker Shearn

Retrospective Theses and Dissertations

Inositol polyphosphate 4-phosphatases (IP4Ps) are lipid phosphatases that remove the 4-position phosphate from the lipid second messenger phosphatidylinositol 3,4-bis-phosphate converting it to phosphatidylinositol 3-phosphate. There are 2 families of IP4P's that are 37% homologous to each other denoted type I and type II. Previously, several different isoforms of both type I and type II IP4P had been identified. These include the beta-spliceoforms of both type I and II that contained a hydrophobic tail instead of a hydrophilic tail and a novel deletion spliceoform found in brain tissue that is approximately 1kDa smaller than type Ialpha called type Ialpha2 ...


Escherichia Coli 30s Ribosomal Subunit Assembly: A Novel Role For The Dnak Chaperone System , Jennifer Anne Maki Jan 2004

Escherichia Coli 30s Ribosomal Subunit Assembly: A Novel Role For The Dnak Chaperone System , Jennifer Anne Maki

Retrospective Theses and Dissertations

The prokaryotic ribosome is a 2.5 MDa particle comprised of two asymmetric subunits, the large (50S) and small (30S) subunits. The large subunit contains two RNAs (5S and 23S) in addition to thirty-four proteins. The small subunit consists of one RNA (16S rRNA) and twenty-one proteins. Although the crystal structure has been solved, much remains to be revealed concerning the assembly of this macromolecular structure. Our laboratory is focused on the assembly of the small subunit. In vitro assembly of this structure was achieved in the late 1960's and early 1970's. At low temperature when 16S rRNA ...


Development Of A Gene Transfer System In Clostridium Scindens Vpi 12708, Rashmi Ramasubbaiah Jan 2004

Development Of A Gene Transfer System In Clostridium Scindens Vpi 12708, Rashmi Ramasubbaiah

Masters Theses & Specialist Projects

Clostridium scindens VPI 12708 (previously known as Eubacterium sp. VPI 12708) is a bile-acid dehydroxylating bacterium originally isolated from the feces of a colon cancer patient. Many genes required for bile acid 7-a dehydroxylation are found on a large bile acid inducible operon (bai) that has been extensively studied. However the bai promoter, which directs expression of the bai operon, has yet to be characterized due, in part, to a lack of a functional genetic transfer system for this strain. A spontaneous rifampinresistant Clostridium scindens VPI 12708 mutant was used as a recipient to determine the efficacy of conjugation as ...