ETD at Indian Institute of Science
Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.
Molecular Biophysics Unit (mbu)
Mostrando recursos 1 - 20 de 111
Structure Analysis Of Plant Lectin Domains - Shetty, Kartika N
Lectins are multivalent carbohydrate binding proteins that specifically recognise diverse sugar structures and mediate a variety of biological processes, such as cell-cell and host-pathogen interactions, serum glycoprotein turnover and innate immune responses. Lectins have received considerable attention in recent years on account of their properties leading to wide use in research and biomedical applications. Seeds of leguminous plants are mainly rich sources of lectins, but lectins are also found in all classes and families of organisms. Legume lectins have similar tertiary structures, but exhibit a large variety of quaternary structures. The carbohydrate binding site in them is made up of...
Mechanistic And Regulatory Aspects Of The Mycobacterium Tuberculosis Dephosphocoenzyme A Kinase - Walia, Guneet
The current, grim world-TB scenario, with TB being the single largest infectious disease
killer, warrants a more effective approach to tackle the deadly pathogen, Mycobacterium
tuberculosis. The deadly synergy of this pathogen with HIV and the emergence of drugresistant strains of the organism present a challenge for disease treatment (Russell et al., 2010). Thus, there is a pressing need for newer drugs with faster killing-kinetics which can claim both the actively-multiplying and latent forms of this pathogen causing the oldest known disease to man. This thesis entitled “Mechanistic and Regulatory Aspects of the Mycobacterium tuberculosis Dephosphocoenzyme A Kinase” describes one such potential...
Conformational Analysis And Design Of Disulfides In Antiparallel β-Sheets And Helices - Indu, S
Disulfides are the primary covalent interactions within a protein molecule that connect residues which are sequentially distant. Naturally occurring disulfides enhance the stability of the protein by destabilization of the unfolded state. Previous attempts to introduce disulfide bridges as a means to enhance protein stability have met with mixed results. Tools have been developed to predict potential sites for disulfide introduction. However, it must be noted that engineering disulfides is not a trivial task. The effect of the engineered disulfide on protein stability is difficult to predict. There have been few systematic studies carried out to study disulfides in the...
Structure Analysis Of FabI And FabZ Enzymes Of The Fatty Acid Biosynthesis Pathway Of Plasmodium Falciparum - Maity, Koustav
The emergence of drug resistant strains of Plasmodium has given a new face to the old disease, malaria. One of the approaches is to block metabolic pathways of the pathogen. The current thesis describes the X-ray crystallographic analysis of two enzymes of the fatty acid biosynthesis pathway of the malaria parasite Plasmodium falciparum. In order to understand the functional mechanism and mode of inhibitor binding, enzyme-inhibitor complexes were characterized, which could help in further improvement of the efficacy of the inhibitors and hence to fight against the disease.
The introductory chapter of the thesis presents a discussion on malaria and...
Metabolic Adaptation For Utilization Of Short-Chain Fatty Acids In Salmonella Typhimurium : Structural And Functional Studies On 2-methylcitrate Synthase, Acetate And Propionate Kinases - Chittori, Sagar
Three-dimensional structures of proteins provide insights into the mechanisms of macromolecular assembly, enzyme catalysis and mode of activation, substrate-specificity, ligand-binding properties, stability and dynamical features. X-ray crystallography has become the method of choice in structural biology due to the remarkable methodological advances made in the generation of intense X-ray beams with very low divergence, cryocooling methods to prolong useful life of irradiated crystals, sensitive methods of Xray diffraction data collection, automated and fast methods for data processing, advances and automation in methods of computational crystallography, comparative analysis of macromolecular structures along with parallel advances in biochemical and molecular biology methods...
Sequence Analysis And Design Of Immunogens From The Stem Domain Of Influenza Hemagglutinin - Bommakanti, Gayathri
Influenza is an important respiratory pathogen that infects several million people each year. Currently available flu vaccines have to be updated regularly in order to be effective as the virus changes its composition by antigenic drift and shift. Most of the antibody response generated by these vaccines is strain specific as it is directed against the head domain (HA1) of HA.
The HA2 subunit of hemagglutinin is highly conserved and immunogens designed from this subunit are likely to provide protection against multiple strains of the virus. However, expression of HA2 alone in the absence of HA1 resulted in a protein...
Structural And Mechanistic Studies On Receptor Protein Tyrosine Phosphatases From Drosophila Melanogaster - Madan, Lalima Lochan
Protein Tyrosine Phosphatases (PTPs) initiate, modulate and terminate key cellular processes by dephosphorylating phosphotyrosine (pY) residues on signaling proteins. The coordinated action of PTPs with their cognate tyrosine kinases is crucial for the maintenance of cellular homeostasis. Five Receptor Tyrosine Phosphatases (RPTPs) DLAR, PTP99A, PTP69D,PTP10D and PTP52F are involved in the axon guidance process of the fruit-fly Drosophila melanogaster. The receptors in these RPTPs comprise of Cell Adhesion Molecules (CAMs) whilethe cytosolic region contains the catalytic PTP domains. Extensive studies on the genetic interactions between these RPTPs reveal that these five RPTPs collaborate, compete or are partially redundant in some...
Structural Studies On Three-Fold Symmetric Plant Lectins - Sharma, Alok
Lectins, multivalent carbohydrate-binding proteins of non-immune origin, have the unique ability to decode the information contained in complex carbohydrate structures of glycoproteins and glycolipids by stereo-specifically recognizing and binding to carbohydrates and carbohydrate linkages. The ubiquitous distribution of lectins in all forms of life and viruses along with their involvement in various biological processes such as cell-cell communication, host-pathogen interaction, cancer metastasis, embryogenesis, tissue development and mitogenic stimulation further emphasizes the importance of lectins in biological systems. Although not much is known about the endogenous roles of plant lectins, they constitute the most thoroughly studied class of lectins. On the...
Insights Into The Mechanistic Details Of The M.Tuberculosis Pantothenate Kinase : The Key Regulatory Enzyme Of CoA Biosynthesis - Parimal Kumar, *
Tuberculosis (TB), caused by Mycobacterium tuberculosis, has long been the scourge of humanity, claiming millions of lives. It is the most devastating infectious disease of the world in terms of mortality as well as morbidity (WHO, 2009). The lack of a uniformly effective vaccine against TB, the development of resistance in the Mycobacterium tuberculosis against the present antitubercular drugs and its synergy with AIDS has made the situation very alarming. This therefore necessitates a search for new antitubercular drugs as well as the identification of new and unexplored drug targets (Broun et aI., 1992). Coenzyme A is an essential cofactor...
Structural Studies On Physalis Mottle Virus Capsid Proteins & Stress Response Proteins Of Oryza Sativa And Salmonella Typhimurium - Sagurthi, Someswar Rao
X-ray crystallography is one of the most powerful tools for the elucidation of the structure of biological macromolecules such as proteins and viruses. Crystallographic techniques are extensively used for investigations on protein structure, ligand-binding, mechanisms of enzyme catalyzed reactions, protein-protein interactions, role of metal ions in protein structure and function, structure of multi-enzyme complexes and viruses, protein dynamics and for a myriad other problems in structural biology. Crystallographic studies are essential for understanding the intricate details of the mechanism of action of enzymes at molecular level. Understanding the subtle differences between the pathogenic enzymes and host enzymes is necessary for...
Promoter Prediction In Microbial Genomes Based On DNA Structural Features - Rangannan, Vetriselvi
Promoter region is the key regulatory region, which enables the gene to be
transcribed or repressed by anchoring RNA polymerase and other transcription factors, but it is difficult to determine experimentally. Hence an in silico identification of promoters is crucial in order to guide experimental work and to pin point the key region that controls the transcription initiation of a gene. Analysis of various genome sequences in the vicinity of experimentally identified transcription start sites (TSSs) in prokaryotic as well as eukaryotic genomes had earlier indicated that they have several structural features in common, such as lower stability, higher curvature and...
Protein-DNA Graphs And Interaction Energy Based Protein Structure Networks - Vijayabaskar, M S
Proteins orchestrate a number of cellular processes either alone or in concert with other biomolecules like nucleic acids, carbohydrates, and lipids. They exhibit an intrinsic ability to fold de novo to their functional states. The three–dimensional structure of a protein, dependent on its amino acid sequence, is important for its function. Understanding this sequence– structure–function relationship has become one of the primary goals in biophysics. Various experimental techniques like X–ray crystallography, Nuclear Magnetic Resonance (NMR), and site–directed mutagenesis have been used extensively towards this goal. Computational studies include mainly sequence based, and structure based approaches. The sequence based approaches such...
Topology-based Sequence Design For Proteins Structures And Statistical Potentials Sensitive To Local Environments - Jha, Anupam Nath
Proteins, which regulate most of the biological activities, perform their functions through their unique three-dimensional structures. The folding process of this three dimensional structure from one dimensional sequence is not well understood. The available facts infer that the protein structures are mostly conserved while sequences are more tolerant to mutations
i.e. a number of sequences can adopt the same fold. These arch of optimal sequences for a chosen conformation is known as inverse protein folding and this thesis takes this approach to solve the enigmatic problem.
This thesis presents a protein sequence design method based on the native state topology of protein...
Structural, Biophysical And Biochemical Studies On Mannose-Specific Lectins - Gupta, Garima
For a long time, the scientific community underestimated the value of carbohydrates and the approach of most scientists to the complex world of glycans was apprehensive. The scenario, however, has changed today. With the development of new research tools and methodologies the study of carbohydrates and glycoconjugates has progressed rapidly, increasing our understanding of these molecules. Carbohydrates are most abundant amongst biological polymers in nature and vital for life processes. In their simplest form, they serve as a primary source of energy to most living organisms. In generalis, they exist as complex structures (glycans), and as conjugates of protein (glycoproteins,...