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Molecular Biology

1996

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Articles 1 - 30 of 36

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

The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David S. Peabody Dec 1996

The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David S. Peabody

Marc Spingola

The coat proteins of the RNA bacteriophages Qβ and MS2 are specific RNA binding proteins. Although they possess common tertiary structures, they bind different RNA stem loops and thus provide useful models of specific protein-RNA recognition. Although the RNA-binding site of MS2 coat protein has been extensively characterized previously, little is known about Qβ. Here we describe the isolation of mutants that define the RNA-binding site of Qβ coat protein, showing that, as with MS2, it resides on the surface of a large β-sheet. Mutations are also described that convert Qβ coat protein to the RNA binding specificity of MS2 ...


Expression Of A Dominant Negative Wnt Blocks Induction Of Myod In Xenopus Embryos, Stephan Hoppler, Jeffrey D. Brown, Randall T. Moon Nov 1996

Expression Of A Dominant Negative Wnt Blocks Induction Of Myod In Xenopus Embryos, Stephan Hoppler, Jeffrey D. Brown, Randall T. Moon

Biology Faculty Publications and Presentations

During gastrulation of Xenopus embryos the prospective mesoderm is induced initially with domains of dorsal and ventral fate, then further patterned to generate somitic mesoderm by signals from the gastrula organizer. Although Xwnt-8 is expressed in future ventrolateral mesoderm and induces prospective epidermis to differentiate in vitro as ventral mesoderm, no loss-of-function studies have demonstrated a requirement for Wnt signaling for the normal expression of mesodermal genes in the gastrula. We report development of a dominant-negative Wnt (dnXwnt-8) that inhibits embryonic responses to Wnt signaling in a cell-nonautonomous fashion. By expressing dnXwnt-8 in Xenopus embryos, we uncover a ...


Mechanisms Of Cytokine-Mediated Localized Immunoprotection., Nora Sarvetnick Nov 1996

Mechanisms Of Cytokine-Mediated Localized Immunoprotection., Nora Sarvetnick

Journal Articles: Regenerative Medicine

No abstract provided.


Pancreatic Expression Of Interleukin-4 Abrogates Insulitis And Autoimmune Diabetes In Nonobese Diabetic (Nod) Mice., Regula Mueller, Troy Krahl, Nora Sarvetnick Sep 1996

Pancreatic Expression Of Interleukin-4 Abrogates Insulitis And Autoimmune Diabetes In Nonobese Diabetic (Nod) Mice., Regula Mueller, Troy Krahl, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Diabetes in nonobese diabetic (NOD) mice is a T cell-dependent autoimmune disease. The destructive activities of autoreactive T cells have been shown to be tightly regulated by effector molecules. In particular, T helper (Th) 1 cytokines have been linked to diabetes pathogenesis, whereas Th2 cytokines and the cells that release them have been postulated to be protective from disease. To test this hypothesis, we generated transgenic NOD mice that express interleukin (IL) 4 in their pancreatic beta cells under the control of the human insulin promoter. We found that transgenic NOD-IL-4 mice, both females and males, were completely protected from ...


Local And Distant Sequences Are Required For Efficient Readthrough Of The Barley Yellow Dwarf Virus Pav Coat Protein Gene Stop Codon, Chris M. Brown, S. P. Dinesh-Kumar, W. Allen Miller Sep 1996

Local And Distant Sequences Are Required For Efficient Readthrough Of The Barley Yellow Dwarf Virus Pav Coat Protein Gene Stop Codon, Chris M. Brown, S. P. Dinesh-Kumar, W. Allen Miller

Plant Pathology and Microbiology Publications

Many viruses use stop codon readthrough as a strategy to produce extended coat or replicase proteins. The stop codon of the barley yellow dwarf virus (PAV serotype) coat protein gene is read through at a low rate. This produces an extended polypeptide which becomes part of the virion. We have analyzed the cis-acting sequences in the barley yellow dwarf virus PAV genome required for this programmed readthrough in vitro in wheat germ extracts and reticulocyte lysates and in vivo in oat protoplasts. Two regions 3' to the stop codon were required. Deletion of sections containing the first 5 of the ...


Distribution Of Poly(Adp-Ribose) Glycohydrolase In Different Functional Domains Of The Cell Nucleus, Gustavo Pacheco-Rodriguez B.S., M.S. Aug 1996

Distribution Of Poly(Adp-Ribose) Glycohydrolase In Different Functional Domains Of The Cell Nucleus, Gustavo Pacheco-Rodriguez B.S., M.S.

Theses and Dissertations

Pacheco-Rodriguez, Gustavo, Distribution of Poly(ADP-ribose) Glycohydrolase in Different Functional Domains of the Cell Nucleus. Doctor of Philosophy (Biomedical Sciences), August, 1996, 147 pp, 3 tables, 44 illustrations, bibliography, 138 titles. In this study, the distributor poly(ADP-ribose) glycohydrolase (PARG) in different subdomains of the cell nucleus and the role of non-covalent interactions of poly(ADP-ribose) with nuclear proteins have been characterized. An assay that allows the simultaneous determination of specific non-covalent interactions of poly (ADP-ribose) with nuclear proteins as well as PARG activity by high resolution polyacrylamide gel electrophoresis was developed. This method was made possible by the enzymatic ...


Functional Mapping Of The Translation-Dependent Instability Element Of Yeast Matalpha1 Mrna, Aidan N. Hennigan, Allan Jacobson Jul 1996

Functional Mapping Of The Translation-Dependent Instability Element Of Yeast Matalpha1 Mrna, Aidan N. Hennigan, Allan Jacobson

Open Access Articles

The determinants of mRNA stability include specific cis-acting destabilizing sequences located within mRNA coding and noncoding regions. We have developed an approach for mapping coding-region instability sequences in unstable yeast mRNAs that exploits the link between mRNA translation and turnover and the dependence of nonsense-mediated mRNA decay on the activity of the UPF1 gene product. This approach, which involves the systematic insertion of in-frame translational termination codons into the coding sequence of a gene of interest in a upf1delta strain, differs significantly from conventional methods for mapping cis-acting elements in that it causes minimal perturbations to overall mRNA structure. Using ...


Il-10 Is Necessary And Sufficient For Autoimmune Diabetes In Conjunction With Nod Mhc Homozygosity., Myung-Shik Lee, Regula Mueller, Linda S. Wicker, Laurence B. Peterson, Nora Sarvetnick Jun 1996

Il-10 Is Necessary And Sufficient For Autoimmune Diabetes In Conjunction With Nod Mhc Homozygosity., Myung-Shik Lee, Regula Mueller, Linda S. Wicker, Laurence B. Peterson, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Contrary to expectations based on in vitro experiments, we previously found that pancreatic IL-10 did not inhibit autoimmune diabetes but accelerated it in an MHC-dependent manner. Therefore, the ability of IL-10 to overcome the absence of all non-MHC diabetes susceptibility (Idd) alleles was studied in transgenic mice expressing pancreatic IL-10 backcrossed to B10.H2g7 congenic mice, which have no Idd alleles other than NOD MHC (H2g7). IL-10 transgenic backcross 1 (BC1) mice with H2g7/g7 haplotype developed clear-cut insulitis and diabetes, but neither transgenic mice with the H2g/b haplotype nor nontransgenic BC1 mice did so. Further implicating IL-10 in ...


Phylogenic Studies Of The United States Bluetongue Viruses And Characterization Of The Viral Vp4 Protein, I-Jen Huang May 1996

Phylogenic Studies Of The United States Bluetongue Viruses And Characterization Of The Viral Vp4 Protein, I-Jen Huang

All Graduate Theses and Dissertations

Bluetongue virus (BTV) is transmitted by arthropod vectors and causes bluetongue disease with serious economic loss in many regions of the world. The replication mechanism of bluetongue virus is still not clear. To have a better understanding regarding the viral replication, the function of each individual protein has to be identified. This study used molecular biology techniques to investigate the function of the inner core protein VP4.

The M1 genes of United States bluetongue virus serotypes-2, -10, -11, -13, and -17 were cloned and sequenced. The length of each of the five M1 genes is 1981 nucleotides. The coding region ...


Interactions Involving The Human Rna Polymerase Ii Transcription/Nucleotide Excision Repair Complex Tfiih, The Nucleotide Excision Repair Protein Xpg, And Cockayne Syndrome Group B (Csb) Protein, Narayan Iyer, Michael S. Reagan, Kou-Juey Wu, Bertram Canagarajah, Errol C. Friedberg Feb 1996

Interactions Involving The Human Rna Polymerase Ii Transcription/Nucleotide Excision Repair Complex Tfiih, The Nucleotide Excision Repair Protein Xpg, And Cockayne Syndrome Group B (Csb) Protein, Narayan Iyer, Michael S. Reagan, Kou-Juey Wu, Bertram Canagarajah, Errol C. Friedberg

Biology Faculty Publications

The human basal transcription factor TFIIH plays a central role in two distinct processes. TFIIH is an obligatory component of the RNA polymerase II (RNAP II) transcription initiation complex. Additionally, it is believed to be the core structure around which some if not all the components of the nucleotide excision repair (NER) machinery assemble to constitute a nucleotide excision repairosome. At least two of the subunits of TFIIH (XPB and XPD proteins) are implicated in the disease xeroderma pigmentosum (XP). We have exploited the availability of the cloned XPB, XPD, p62, p44, and p34 genes (all of which encode polypeptide ...


A Novel, Mitogen-Activated Nuclear Kinase Is Related To A Drosophila Developmental Regulator, Gerald V. Denis, Michael R. Green Feb 1996

A Novel, Mitogen-Activated Nuclear Kinase Is Related To A Drosophila Developmental Regulator, Gerald V. Denis, Michael R. Green

Open Access Articles

Although the ultimate targets of many signal transduction pathways are nuclear transcription factors, the vast majority of known protein kinases are cytosolic. Here, we report on a novel human kinase that is present exclusively in the nucleus. Kinase activity is increased upon cellular proliferation and is markedly elevated in patients with acute and chronic lymphocytic leukemias. We have identified a human gene that encodes this nuclear kinase and find that it is closely related to Drosophila female sterile homeotic (fsh), a developmental regulator with no known biochemical activity. Collectively, these results suggest that this nuclear kinase is a component of ...


Rosalyn Sussman Yalow (1921-) Endocrinologist, Medical Physicist, Margaret Sylvia Jan 1996

Rosalyn Sussman Yalow (1921-) Endocrinologist, Medical Physicist, Margaret Sylvia

Faculty Publications

A biography of Rosalyn Yalow, Nobel Prize winner in Physiology/Medicine for the development of radioimmunoassay of peptides hormones. She was the second woman to win a Nobel Prize in Medicine and first American woman to do so.


Application Of A Modified Ziehl-Neelsen's Carbol-Fuchsin Stain For Observing Nuclei In Vegetative Hyphae Of The Puffball Species Lycoperdon Pyriforme, Martin J. Huss Jan 1996

Application Of A Modified Ziehl-Neelsen's Carbol-Fuchsin Stain For Observing Nuclei In Vegetative Hyphae Of The Puffball Species Lycoperdon Pyriforme, Martin J. Huss

Journal of the Arkansas Academy of Science

Nuclei of vegetative hyphae of the puffball species Lycoperdon pyriforme are small and difficult to stain. A simple mitotic staining technique utilizing a modified version of Ziehl-Neelsen's carbol-fuchsin stain, originally developed for examining bacteria and small chromosomes of plants, has proven useful for observing fungal nuclei in this gasteromycete species. Cells of vegetative hyphae were pre-treated for 2 hours with an aqueous solution saturated with naphthalene, fixed in a 3:1 mixture of 100% ethanol and glacial acetic acid, and hydrolyzed for 10 minutes in a 1:1 mixture of 100% ethanol and 12 M hydrochloric acid. Cells were ...


Role Of Immunodominant T Cell Responses To Minor Histocompatibility Antigens In A Mouse Model Of Graft-Versus-Host Disease, Marc Adam Berger, B.S. Thomas Jefferson University Jan 1996

Role Of Immunodominant T Cell Responses To Minor Histocompatibility Antigens In A Mouse Model Of Graft-Versus-Host Disease, Marc Adam Berger, B.S. Thomas Jefferson University

Theses & Dissertations

Graft-versus-host-disease (GVHD) is a major complication of major histocompatibility complex (MHC) matched bone marrow transplantation. GVHD is the result of an immune-mediated attack, by T lymphocytes derived from donor bone marrow, against recipient tissues expressing minor histocompatibility antigen (miHA) differences. There is a lack of knowledge concerning the nature of in vivo immune responses to miHA during GVHD. C57BL/6By (B6/By) and BALB.B mouse strains both express the H-2B MHC haplotype but differ at more than 40 miHA loci. Both the in vitro and in vivo T cell responses to miHA expressed by BALB.B and CXB recombinant ...


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 ...


Identification Of Mouse Sip24/24p3 As A New Acute Phase Protein And Study Of Its Expression , Quansheng Liu Jan 1996

Identification Of Mouse Sip24/24p3 As A New Acute Phase Protein And Study Of Its Expression , Quansheng Liu

Retrospective Theses and Dissertations

Mouse SIP24 was originally discovered as a 24 k Da inducible protein secreted from quiescent Balb/c 3T3 fibroblast cells. Based on the analysis of peptide sequencing results and Western blot studies, SIP24 was identified as identical to the mouse protein encoded by 24P3 and is thus referred to as SIP24/24P3 in this thesis. SIP24/24P3 is a member of the lipocalin protein family, and its human homolog NGAL (neutrophil gelatinase associated lipocalin) has been reported to bind the chemotactic factor, fMLP (N-formylmethionyl-leucyl-phenylalanine);Studies were carried out to test the hypothesis that SIP24/24P3 is an acute phase protein ...


Purification, Characterization And Molecular Cloning Of Muscle Paranemin , Philip Mark Hemken Jan 1996

Purification, Characterization And Molecular Cloning Of Muscle Paranemin , Philip Mark Hemken

Retrospective Theses and Dissertations

Paranemin is an incompletely characterized ~280 kilodalton protein previously identified and immunolocalized in embryonic chick skeletal muscle. Paranemin has been purified from the same tissue source, has the same molecular weight by SDS-PAGE, and has the same antibody localization at the Z-lines of adult avian cardiac muscle. The method developed for preparation of purified paranemin from embryonic (chick) skeletal muscle includes homogenization, centrifugation and gel filtration, hydroxyapatite, and DEAE-cellulose chromatography. By using this method, ~2 mg of purified paranemin was routinely obtained. Amino acid analysis revealed that paranemin has a high acidic to basic amino acid ratio, which agrees with ...


Molecular Marker Analysis Of Iron Efficiency In Soybean (Glycine Max (L.) Merr.) , Shun-Fu Lin Jan 1996

Molecular Marker Analysis Of Iron Efficiency In Soybean (Glycine Max (L.) Merr.) , Shun-Fu Lin

Retrospective Theses and Dissertations

The objectives of the studies were to map genes affecting iron deficiency chlorosis in soybean, to test the hypothesis that two genetic mechanisms control iron deficiency chlorosis in soybean, and to determine the effectiveness of nutrient solution evaluation for iron deficiency chlorosis in soybean. Chlorosis symptoms of one hundred and twenty F2:4 lines from a Pride B216 x A15 population, and 92 F2:4 lines from an Anoka x A7 population grown in a field of calcareous soil in 1993 and 1994 were evaluated by visual scores and spectrometric chlorophyll determinations. Each population also was evaluated separately with two ...


Integration Specificity Of The Retrovirus-Like Transposable Element Ty5 Of Saccharomyces , Sige Zou Jan 1996

Integration Specificity Of The Retrovirus-Like Transposable Element Ty5 Of Saccharomyces , Sige Zou

Retrospective Theses and Dissertations

The retrotransposons and retroviruses display a strong preference in selecting integration sites. The molecular mechanisms underlying this process, however, are largely unknown. I have characterized a new retrotransposon, called Ty5, in diverse strains of Saccharomyces cerevisiae and related species. A functional element, Ty5-6p, was identified from S. paradoxus. To investigate Ty5 target preference, the locations of 13 native insertions were determined in S. cerevisiae and S. paradoxus. Twelve were found near the telomeres and the mating locus HMR. To determine if this distribution is a consequence of targeted integration, a Ty5 transposition assay was developed in S. cerevisiae using Ty5-6p ...


Cloning Of Bovine Intercellular Adhesion Molecules And Characterization Of Expression Of Neutrophil Adhesion Molecules In Periparturient Cows And Calves , Eunkyung Lee Jan 1996

Cloning Of Bovine Intercellular Adhesion Molecules And Characterization Of Expression Of Neutrophil Adhesion Molecules In Periparturient Cows And Calves , Eunkyung Lee

Retrospective Theses and Dissertations

The interactions of circulating leukocytes with the endothelium represent a key point in the effector functions of the immune system by regulating the specificity and strength of cell-cell interactions. The recruitment of neutrophils to sites of inflammation is initiated by chemoattractants. The initial contact of neutrophils on vascular endothelial cells is a rolling interaction mediated by members of the selectin family. These include E-selectin and P-selectin on the surface of activated endothelial cells, and L-selectin on neutrophils. The subsequent activation of leukocyte [beta]2 integrins, which bind to the glycoprotein intercellular adhesion molecule-1 (ICAM-1) on endothelial cells, is essential for ...


Genetic Construction And Biochemical Analysis Of Thermostability Mutants Of Glucoamylase From Aspergillus Awamori , Yuxing Li Jan 1996

Genetic Construction And Biochemical Analysis Of Thermostability Mutants Of Glucoamylase From Aspergillus Awamori , Yuxing Li

Retrospective Theses and Dissertations

To study the molecular basis of Aspergillus awamori glucoamylase (GA) thermostability, eighteen mutants were constructed by site-directed mutagenesis and expressed in Saccharomyces cerevisiae based on thermostability theories. Four lysine residues, K61, K279, K352 and K404, were replaced with arginine, with all but K404 well exposed to the solvent and far away from the enzyme activity site. Mutations K61F/D65E and H254W/E326Q were made to fill a packing void around the inner set of six [alpha]-helices of GA and to displace water molecules inside the void. Five residues (A27, A393, A435, Ser436 and Ser460) were replaced with proline. Two ...


The Structure And Function Of Human Brain Hexokinase , Chenbo Zeng Jan 1996

The Structure And Function Of Human Brain Hexokinase , Chenbo Zeng

Retrospective Theses and Dissertations

An ATP binding site model for human brain hexokinase was established based on the similarity of the ATP-binding domains among actin, heat shock protein, glycerol kinase and brain hexokinase. Site directed mutagenesis was performed on the residues in the putative ATP-binding site in order to substantiate or refute the proposed model. The k cat values decreased 1000- and 200-fold for the Asp532Lys and Asp532Glu mutants, 114- and 12-fold for the Arg539Ile and Arg539Lys mutants, 2000- and 2-fold for the Thr680Val and Thr680Ser mutants, respectively. It is suggested that these residues are important for catalysis by either keeping the [gamma]-phosphoryl ...


Evidence That Heparin Affects Protein Levels Of Three Extracellular Matrix Glycoproteins, Kimberly J. Sebo Jan 1996

Evidence That Heparin Affects Protein Levels Of Three Extracellular Matrix Glycoproteins, Kimberly J. Sebo

Theses and Dissertations

No abstract provided.


Studies On The Structure-Function Relationships And Regulation Mechanisms Of Escherichia Coli Adenylosuccinate Synthetase , Wenyan Wang Jan 1996

Studies On The Structure-Function Relationships And Regulation Mechanisms Of Escherichia Coli Adenylosuccinate Synthetase , Wenyan Wang

Retrospective Theses and Dissertations

Molecular biological, biochemical, and biophysical techniques were utilized to explore structure-function relationship of Escherichia coli adenylosuccinate synthetase. For the first time, residues Arg303, Arg304 and Arg305 were implicated as the determinants in the recognition and binding of substrate L-aspartate. Replacing Arg305 with leucine resulted in over a 100-fold decrease in kcat, suggesting a possible role of Arg305 in catalysis. pH dependent kinetic studies indicated that the side chain of Gln224 is not only involved in recognition of IMP, but also in stabiling the intermediate 6-phosphoryl-IMP. Substitution of the side chain amide with a carboxylate group resulted in loss of catalytic ...


Biology Of Rpv Barley Yellow Dwarf Virus Satellite Rna , Lada Rasochova Jan 1996

Biology Of Rpv Barley Yellow Dwarf Virus Satellite Rna , Lada Rasochova

Retrospective Theses and Dissertations

Satellite RNAs (satRNAs) depend on their helper viruses for replication, encapsidation and spread. The goal of the research was to determine helper virus specificity and host range of the RPV barley yellow dwarf luteovirus (BYDV-RPV) satRNA (satRPV RNA) and assay satRPV RNA for the ability to affect the accumulation and modulate disease symptoms of its helper viruses in protoplasts and plants. Although similar in structural genes, subgroup I and II luteoviruses have very different polymerases. BYDV-RPV and beet western yellows virus (BWYV), members of subgroup II luteoviruses, supported satRPV RNA replication in monocotyledonous and dicotyledonous hosts, respectively. In contrast, BYDV-PAV ...


Characterization Of Membrane-Associated Nuclease Activity In Mycoplasma Pulmonis , Karalee Jean Jarvill-Taylor Jan 1996

Characterization Of Membrane-Associated Nuclease Activity In Mycoplasma Pulmonis , Karalee Jean Jarvill-Taylor

Retrospective Theses and Dissertations

Mycoplasmas are deficient in numerous biosynthetic pathways. Consequently, growth is dependent upon the acquisition of structural and macromolecular precursors from the environment. These precursors include phospholipids, fatty acids and nucleotide bases. DNases and RNases are postulated to be involved in the acquisition of nucleotides. The goals of this study were to determine if nuclease activities are universally associated with mycoplasmas, characterize the nucleases by subcellular distribution and apparent molecular weight, and to identify and analyze the nuclease gene(s) in Mycoplasma pulmonis;Nuclease activity was present in all mycoplasma species tested. The level of activity did not correlate with virulence ...


Regulation Of Translation By The 3' Untranslated Region Of Barley Yellow Dwarf Virus-Pav Rna , Shanping Wang Jan 1996

Regulation Of Translation By The 3' Untranslated Region Of Barley Yellow Dwarf Virus-Pav Rna , Shanping Wang

Retrospective Theses and Dissertations

Eukaryotic translation initiation is an important step for gene expression. This process is stimulated by the interaction of 5' cap and 3' poly(A) tail mediated by trans-acting factors. Positive sense viral RNA can differ from the cellular mRNA by lacking either a 5' cap, or 3' poly(A) tail or both. Therefore, various strategies have evolved by the RNA viruses to achieve efficient translation. Barley yellow dwarf virus-PAV serotype (BYDV-PAV) lacks both a 5' cap and 3' poly(A) tail. I found that a sequence (called 3'TE for 3' translation enhancer) at the 3'UTR of barley yellow ...


Molecular Characterization Of The Chloroplastic Acetyl-Coa Carboxylase Of Arabidopsis Thaliana , Joong-Kook Choi Jan 1996

Molecular Characterization Of The Chloroplastic Acetyl-Coa Carboxylase Of Arabidopsis Thaliana , Joong-Kook Choi

Retrospective Theses and Dissertations

Acetyl-CoA carboxylase (ACCase) is a biotin-containing enzyme that catalyzes the formation of malonyl-CoA from acetyl-CoA. Dicot plants such as Arabidopsis contain two structurally distinct types of ACCases that are located in different subcellular compartments. The ACCase located in the cytosol of plant cells generates malonyl-CoA for the synthesis of plant secondary metabolites, including a variety of polyketides and derivatives, and malonylated phytochemicals. The ACCase that is located in chloroplasts generates malonyl-CoA for de novo fatty acid biosynthesis. This enzyme has a heteromeric structure consisting of at least four subunits: the biotin-carrier subunit, coded by the CAC1 gene, the biotin carboxylase ...


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 ...


The Use Of Random Peptide Libraries To Define The Epitopes Of Two Hiv Gp41 Monoclonal Antibodies, Beth Arnold Jan 1996

The Use Of Random Peptide Libraries To Define The Epitopes Of Two Hiv Gp41 Monoclonal Antibodies, Beth Arnold

Theses and Dissertations

No abstract provided.