Research Summary

Research in my lab is to study potential drug target proteins encoded in the genome of Mycobacterium tuberculosis (MTB), the causative agent of the disease tuberculosis. We use X-ray crystallographic techniques and in vitro biochemical assays to analyze the functions, reaction mechanism, and protein-protein interactions of these proteins. Current projects include studying the proteins involved in the pantothenate biosynthetic pathway, and the PhoP-PhoR two-component signaling system.

Pantothenate (vitamin B5) is an essential precursor for the biosynthesis of coenzyme A and acyl carrier proteins that play critical roles in many cellular metabolic processes. Humans do not synthesize pantothenate but obtain this essential nutrient from diets. MTB mutants lacking pantothenate biosynthesis are highly attenuated in virulence. We have determined the crystal structure of the pantothenate synthetase (PanC) from MTB and structures of this enzyme in complexes with substrates, a substrate analog, and a reaction intermediate. These structures give a detailed mechanism of the enzyme-catalyzed reaction, and suggest potential inhibitors to the enzyme. We are also studying other enzymes involved in the pantothenate biosynthetic pathway, the aspartate decarboxylase (PanD) and the ketopantoate reductase (PanE) from MTB.

The PhoP-PhoR two-component system is essential for virulence and intracellular growth of MTB. Global profiling of gene expression indicates that at least 44 genes are up-regulated and 70 genes are down-regulated by PhoP-PhoR. A mutant MTB lacking this two-component system has defects in cell envelope, and it cannot grow in human and mouse macrophages or in mice. We are studying the structures of the PhoP and PhoR protein, the interactions between these two proteins, the mechanism of PhoR autophosphorylation and phosphorylation of PhoP, and the DNA recognition mechanism of PhoP. We are also studying the function of PhoP in regulation of gene expression. This project is in close collaboration with the Smith lab at PHRI.

PHRI has several strong research programs on the biology of MTB. The research in my lab complements these MTB biology research programs, and together we aim for a better understanding of the molecular mechanism of MTB interactions with its host cells and for development of better treatments for tuberculosis.




Recent Articles

S. Wang, J. Engohang-Ndong, and I. Smith. Structure of the DNA-binding domain of the response regulator PhoP from Mycobacterium tuberculosis. Biochemistry (2007) In press, Web Release Date: 01-Dec-2007; (Article) DOI: 10.1021/bi700970a.

S. Wang and D. Eisenberg. Crystal Structure of the Pantothenate Synthetase from Mycobacterium tuberculosis, Snapshots of the Enzyme in Action. Biochemistry (2006) 45, 1554-1561.

M. Strong, M. Sawaya, S. Wang, M. Phillips, D. Cascio and D. Eisenberg. Toward the structural genomics of complexes: crystal structure of a PE/PPE protein complex from Mycobacterium tuberculosis. Proc Natl Acad Sci U S A. (2006) 103, 8060-8065.

S. Wang and D. Eisenberg. Snapshots of the pantothenate synthetase from Mycobacterium tuberculosis along the reaction coordinate, in Etter Transactions of the American Crystallographic Association, Vol.1 (2005) 29-41. American Crystallographic Association.

S. Wang and D. Eisenberg. Crystal Structures of a Pantothenate Synthetase from M. tuberculosis and its complexes with substrates and a reaction intermediate. Protein Science (2003) 12, 1097-1108.

C. W. Goulding , L. J. Perry , D. Anderson, M. Sawaya, D. Cascio, M. I. Apostol, S. Chan, A. Parseghian, S. Wang, Y. Wu, V. Cassano, H. S. Gill and D. Eisenberg. Structural genomics of Mycobacterium tuberculosis: a preliminary report of progress at UCLA. Biophysical Chemistry 105 (2003) 361-370.

S. Wang, C. Mura, M. Sawaya, D. Cascio and D. Eisenberg. Crystal Structure of a Nudix Protein from Pyrobaculum aerophilum reveals a dimer with two intersubunit ß sheets. Acta Cryst. (2002) D58, 571-578.

S. Wang, L. Tabernero, M. Zhang, E. Harms, R. L. Van Etten and C. V. Stauffacher. Crystal Structures of a Low Molecular Weight Protein Tyrosine Phosphatase from Saccharomyces cerevisiae and its Complex with the Substrate p-Nitrophenyl Phosphate. Biochemistry (2000) 39, 1903-1914.

S. Wang, C. V. Stauffacher and R. L. Van Etten. Structural and Mechanistic Basis for the Activation of a Low Molecular Weight Protein Tyrosine Phosphatase by Adenine. Biochemistry (2000) 39, 1234-1242.

K. Ostanin, C. Pokalsky, S. Wang and R. L. Van Etten. Cloning and Characterization of a Saccharomyces cerevisiae Gene Encoding the Low Molecular Weight Protein-tyrosine Phosphatase. J. Biol. Chem. (1995) 270, 18491.




Patents

D. Eisenberg, S. Wang and C. Goulding (2006) Anti-Tuberculosis Drugs Based on Pantothenate Synthetase Inhibitors. U.S. Provisional Application No. 60/757,000.




Research Grants

Merck Company Foundation Grant, supporting new investigator on tuberculosis research, 2006-2011, $50,000 per year, PI Shuishu Wang.

National Institute of General Medical Sciences, R01GM079185, Structural and functional studies of a PhoP-PhoR two-component system, 7/20/2007 - 5/31/2012, first year direct costs $171,000, total direct costs in 5 years $912,000, PI Shuishu Wang.




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