Browsing by Author "Shi, Lei"

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    Application of molecular modeling techniques to study the structure, dynamics, and interactions of membrane proteins.
    (2011-08) Shi, Lei
    Membrane proteins constitute ~30% of all the genomes and ~70% of the drug targets. However, less than 1% of the entries in the protein data bank are membrane proteins. The underrepresentation of membrane protein structures limits our understanding of their functions. This thesis summarizes my effects to apply theoretical methods to understand the structure and function relationships of membrane proteins. Specifically, we developed computational techniques to interpret solution and solid-state NMR data of membrane proteins and determine their high resolution structures. We further performed molecular dynamics simulations to study their dynamics, interaction with other proteins and the lipid bilayer environment. We applied these approaches to phospholamban, which is a membrane protein that is involved in cardiac muscle relaxation by regulating Ca2+-ATPase activity. Our results provide new insights to understand how membrane proteins elicit their function.
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    Computational Modeling of Protein Kinase A and Comparison with Nuclear Magnetic Resonance Data
    (2009-10-07) Shi, Lei; Veglia, Gianluigi
    Protein phosphorylation is fundamental in the modulation of myocardial contractility. Sarcoendoplasmic reticulum Ca2+ ATPase(SERCA) removes cytosolic Ca2+ to initiate relaxation, but the regulatory protein, phospholamban(PLN), decreases SERCA’s affinity for free Ca2+. Phosphorylation of PLN by Protein Kinase A (PKA) induces a relief of inhibition on SERCA and augments the rate of SERCA Ca2+ uptake. Here, we studied the interaction between PKA and PLN by nuclear magnetic resonance (NMR), computational docking and molecular dynamics (MD) simulations. Comparative simulations of PKA apo, binary and ternary states were performed, which provided molecular details to understand the mechanism of PKA substrate recognition.