The objective of the proposed studies is to understand the protein-protein interactions involved in the assembly of the bacterial type III secretion needle apparatus. This apparatus resembles a syringe on the bacterial surface and is used by many pathogens to inject virulence factors into target cells to initiate human diseases. The needle-like assembly consists of about 120 copies of identical proteins that are arranged in a superhelical manner, and the apex of this needle is capped by tip proteins. Over the past two years, we have completed the NMR structures of two needle monomers: BsaL from Burkholderia pseudomallei, a pathogen associated with biowarfare, and PrgI from Salmonella typhimurium, a pathogen associated with food poisoning. We have also used NMR to identify the key residues involved in the binding interaction between the needle and tip proteins of Shigella flexneri. Our goal is to elucidate how the needle apparatus is assembled by determining the precise protein-protein contacts involving the needle and tip proteins. We will combine NMR with electron microscopy and molecular modeling to determine the structure of the assembled needle.
Our aims are: (#1) determine how the needle is assembled, (#2) determine how the tip protein docks on the needle, and (#3) use mutagenesis and microbiological assays to correlate the structural results to needle assembly and virulence in vivo. Many pathogens rely on the needle apparatus to infect millions of people worldwide and many are potential agents of bioterrorism. Because this apparatus is exposed on the bacterial surface, disrupting the needle assembly is an attractive approach for the development of novel anti-infectives. This approach requires a detailed understanding of the protein-protein interactions involved in needle assembly.
The appearance of many antibiotic resistant bacterial pathogens poses a major problem in public health and safety and many of these bacteria rely on a needle-like protein assembly to infect their hosts. The proposed research seeks to elucidate how this needle is assembled by determining the protein-protein interactions of its components. This knowledge will then be used in the design of novel anti-bacterial agents.
|McShan, Andrew C; Kaur, Kawaljit; Chatterjee, Srirupa et al. (2016) NMR identification of the binding surfaces involved in the Salmonella and Shigella Type III secretion tip-translocon protein-protein interactions. Proteins 84:1097-107|
|McShan, Andrew C; Anbanandam, Asokan; Patnaik, Sikta et al. (2016) Characterization of the Binding of Hydroxyindole, Indoleacetic acid, and Morpholinoaniline to the Salmonella Typeâ€…III Secretion System Proteins SipD and SipB. ChemMedChem 11:963-71|
|Kaur, Kawaljit; Chatterjee, Srirupa; De Guzman, Roberto N (2016) Characterization of the Shigella and Salmonella Typeâ€…III Secretion System Tip-Translocon Protein-Protein Interaction by Paramagnetic Relaxation Enhancement. Chembiochem 17:745-52|
|McShan, Andrew C; De Guzman, Roberto N (2015) The bacterial type III secretion system as a target for developing new antibiotics. Chem Biol Drug Des 85:30-42|
|Chaudhury, Sukanya; Nordhues, Bryce A; Kaur, Kawaljit et al. (2015) Nuclear Magnetic Resonance Characterization of the Type III Secretion System Tip Chaperone Protein PcrG of Pseudomonas aeruginosa. Biochemistry 54:6576-85|
|Chaudhury, Sukanya; de Azevedo Souza, Clarice; Plano, Gregory V et al. (2015) The LcrG Tip Chaperone Protein of the Yersinia pestis Type III Secretion System Is Partially Folded. J Mol Biol 427:3096-109|
|Lan, Lan; Appelman, Carl; Smith, Amber R et al. (2015) Natural product (-)-gossypol inhibits colon cancer cell growth by targeting RNA-binding protein Musashi-1. Mol Oncol 9:1406-20|
|Rathinavelan, Thenmalarchelvi; Lara-Tejero, Maria; Lefebre, Matthew et al. (2014) NMR model of PrgI-SipD interaction and its implications in the needle-tip assembly of the Salmonella type III secretion system. J Mol Biol 426:2958-69|
|Chatterjee, Srirupa; Chaudhury, Sukanya; McShan, Andrew C et al. (2013) Structure and biophysics of type III secretion in bacteria. Biochemistry 52:2508-17|
|Chaudhury, Sukanya; Battaile, Kevin P; Lovell, Scott et al. (2013) Structure of the Yersinia pestis tip protein LcrV refined to 1.65â€…Ã… resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 69:477-81|
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