BIOCHEMISTRY, BIOINORGANIC CHEMISTRY, AND CHEMICAL BIOLOGY

Fundamentals and Applications in Biological Sensing and Signaling

We seek to understand sensing and signal transduction in bacteria from a molecular to a community level. As we learn more about the fundamentals of nitric oxide signaling in bacteria, known sensor proteins will be used in a modular approach for the design and engineering of new proteins and peptides that either mimic known structure or function or create new structure or function, with the aim of fundamentally understanding the natural system and using this knowledge to develop practical applications, primarily in human health and biotechnology.

PROKARYOTIC NITRIC OXIDE BIOLOGY
Nitric oxide (NO) has diverse and important roles in eukaryotic biology. In addition to its role as a powerful toxin used to kill invading pathogens and tumor cells, NO functions as a signaling molecule that mediates many functions such as smooth muscle relaxation, neuronal signal transduction and inhibition of platelet aggregation. In eukaryotes, the heme group of the enzyme soluble guanylate cyclase (sGC) is the specific receptor of the NO signal. Genomic analysis has recently placed sGC within a larger family of heme proteins including prokaryotic proteins with significant homology (15-40% identity) to the heme domain of sGC, called the H-NOX family, for Heme Nitric oxide and/or OXygen binding domain. What is the function of the H-NOX family in bacteria? Are they NO sensors? The discovery of the H-NOX family has lead to several lines of research in our group.

PEPTIDE AND PROTEIN ENGINEERING FOR NOVEL SENSING APPLICATIONS
Sensing and signal transduction proteins appear to be modularly designed, consisting of a sensing domain and an effector domain. This class of proteins responds to signals such as small molecules, proteins, gases, redox changes, and light; and can transmit these signals through the action of protein kinases, transcription factors, and chemotaxis machinery, among others. Furthermore, proteins often contain a smaller peptide segments that affords functional specificity. Thus we dissect proteins and protein complexes into protein domains and peptides for components in a toolbox used to develop new biosensors and also to answer fundamental questions about uncharacterized sensing modules.

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Leading References

Pellicena, P.; Karow, D.S.; Boon, E.M.; Marletta, M.A.; Kuriyan, J. (2004) Crystal structure of an oxygen-binding heme domain related to soluble guanylate cyclases. PNAS, 101, 12854-12859.

Boon, E.M.; Huang, S.H.; Marletta, M.A. (2005) A molecular basis for NO selectivity in soluble guanylate cyclase. Nat. Chem. Biol., 1, 53-59.

Boon, E.M.; Marletta, M.A. (2005) Ligand discrimination in soluble guanylate cyclase and the H-NOX family of heme sensor proteins. Curr. Op. Chem. Biol., 9, 441-446.

Boon, E.M.; Marletta, M.A. (2005) Ligand specificity of H-NOX domains: From sGC to bacterial NO sensors. J. Inorg. Biochem., 99, 892-902.

Boon, E.M.; Davis, J.H.; Karow, D.S.; Huang, S.H.; Tran, R.; Miazgowicz, M.M.; Mathies, R.; Marletta, M.A. (2006) Characterization of NO binding to prokaryotic homologs of the sGC beta1 H-NOX domain. J. Biol. Chem., 281, 21892-21902.

Boon, E.M.; Marletta, M.A. (2006) Sensitive and selective detection of nitric oxide using an H-NOX domain. J. Am. Chem. Soc., 128, 10022-10023