Chemistry and Chemical Biology ETDs

Publication Date

Fall 12-12-2020

Abstract

Nitric oxide (NO) is generated by one of the three isoforms of mammalian NO synthases (NOSs), neuronal, endothelial and inducible NOS (nNOS, eNOS, and iNOS, respectively). Dysregulated NOS is implicated in pathologies of numerous severe diseases including Alzheimer and Parkinson’s diseases. Molecular mechanisms of NOS regulation, once fully understood, are potentially key targets for development of selective new pharmaceuticals for treating these diseases that currently lack effective treatments.

Despite recent developments, there are significant gaps in current understanding of the regulation mechanism of the FMN-heme interdomain electron transfer (IET), an essential step in NOS, by its key regulators such as calmodulin (CaM) and heat shock protein 90 (Hsp90), and by means of posttranslational modifications (e.g., phosphorylation). It is timely and important to investigate the control mechanism.

Major findings of my dissertation include: 1) Identifying isoform-specific residues at the NOS(heme)-CaM docking interface; 2) Demonstrating that Hsp90 enhances the FMN-heme IET through specific association with nNOS; 3) Establishing a new genetic code expansion protocol by which phosphoserine can be site-specifically incorporated into rat nNOS with high yield and fidelity. Taken together, our results have provided significant insight into the regulation mechanism of electron transfer in NOSs at the molecular level. This is a necessary first step toward rational design of small NOS modulators targeting the dynamic interface related to electron transfer.

Language

English

Keywords

Electron transfer, Nitric oxide synthase, Heat shock protein 90, Kinetics, Superoxide, Phosphoserine

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Changjian Feng

Second Committee Member

Jeremy S. Edwards

Third Committee Member

Mark Walker

Fourth Committee Member

Yi He

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