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The mechanism of transmembrane
electron transfer and active proton pumping by the ubiquitous respiratory enzyme, cytochrome c oxidase (CcO)
is a challenging area of research in bioinorganic chemistry. We have detected redox-state dependent conformational changes in this multi-metal enzyme and has
shown that there is a localized conformational change in the enzyme due the
electron transfer process. Our studies showed that the conformational changes
due to electron transfer and proton translocation are complementary to each
other. Our recent studies on pH induced conformational transition in
genetically engineered dicopper site of cytochrome c oxidase demonstrated the
possible role of this site in the gating mechanism of the electron transfer
process of the enzyme. 
mediated by the metalloenzyme, cytochrome P450. The
mechanism of drug metabolism, substrate recognition and product selectivity by
this enzyme is a frontier area of research in bioinorganic chemistry. Studies of
the interaction of physiologically important substrates with different cytochrome P450 enzymes by us helped to identify subtle conformational changes
near the heme active site of the enzyme. 
ing, ionic and hydrophobic
interactions on the stabilization of the active site in the plant peroxidase and
showed that the high stability of the enzyme against hydrogen peroxidase arises
due to extensive hydrogen bonding and salt-bridges surrounding the metal center
in the enzyme. Removal of the metal ion prosthetic group was shown to have a
drastic effect on the structure of the enzyme and Our studied have also shown
existence of multiple conformational sub-states in the apo-protein of the
peroxidase in solution.
significant role in the
biochemical function and stability of these biomolecules. We have shown that
while ionic surfactants deactivate and cause depletion of the metal prosthetic
group from most of the metal proteins, neutral surfactants help to stabilize the active structure in them. Our work has also suggested that the cardiotoxicity of
the anti-cancer drug, adriamycin possibly arises due to seggregation of the
functional lipid, cardiolipins associated with the cytochrome c oxidase leading
to deactivation of the enzyme. We have shown that ionic surfactants can
selectively unfold the metal active site of cytochrome c and stabilize an
intermediate species, which is formed in the unfolding pathway of the enzyme.
These studies have elucidated a fascinating chemistry of the action of
surfactants and helped in better understanding of the varying degree of
structural rigidity in the metal proteins. | · |
Reversible inactivation of cytochrome P450 by alkaline earth metal ions: Auxiliary metal ion induced conformation change and formation of inactive P420 species in CYP101 Soumen K. Manna, Shyamalava Mazumdar |
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Effect of Polar Solvents on the Optical Properties of Water-dispersible Thiol-Capped Cobalt Nanoparticles Nusrat J M Sanghamitra and Shyamalava Mazumdar |
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Conformational dynamics coupled to protonation equilibrium at the CuA site of T. thermophilus: Insights into the origin of thermostability Nusrat J.M. Sanghamitra and Shyamalava Mazumdar |
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Thermostability of proteins: Role metal binding and pH on the stability of the dinuclear CuA site of Thermus thermophilus A. Sujak, Nusrat J. M. Sanghamitra, O. Maneg, B. Ludwig and Shyamalava Mazumdar |
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Effect of Alcohols on Binding of Camphor to Cytochrome P450cam: Spectroscopic and Stopped Flow Transient Kinetic Studies R. Murugan and Shyamalava Mazumdar |
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Role of Threonine 101 on the stability of the heme active site of cytochrome P450cam: Multi-wavelength Circular Dichroism Studies Soumen Kanti Manna and Shyamalava Mazumdar |
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Structure of the heme centre and its redox properties in the C357M mutant of cytochrome P450cam R. Murugan and S. Mazumdar |
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Direct Correlation of the Crystal Structure of Proteins with the Maximum Positive and Negative Charge-States of Gaseous Protein Ions Produced by Electrospray Ionization Halan Prakash and S. Mazumdar |
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Role of substrate on the conformational stability of the heme active site of cytochrome P450cam: effect of temperature and low concentrations of denaturants |
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Stabilization of Partially Folded States of Cytochrome C in Aqueous Surfactant: Effects of Ionic and Hydrophobic Interactions K. Chattopadhyay and S. Mazumdar |
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pH induced conformational transition in the soluble CuA domain of Paracoccus denitrificans cytochrome oxidase S. Gupta, A. Warne, Matti Saraste and S. Mazumdar |
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Redox Linked Conformational Change in Bovine Heart Cytochrome c Oxidase: Picosecond Time-resolved Fluorescence Studies of the Cyanide Complex T. K. Das and S. Mazumdar |
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Structural and Conformational Stability of Horseradish Peroxidase: Effect of Temperature and pH K. Chattopadhyay and S. Mazumdar |
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Direct electrochemical oxidation of horseradish peroxidase: Cyclic Voltammetric and spectroelectrochemical studies K. Chattopadhyay and S. Mazumdar |