Gram-positive bacteria are the causative agents of many nosocomial infections and diseases including osteomyelitis and pneumonia. The majority of Gram-positive bacteria harbor sortases, which are transpeptidases that recognize a short peptide sequence found near the C-terminus of proteins. Proteins harboring this recognition motif are subsequently anchored to the peptidoglycan and are required to establish infection by acting as adhesins or by mediating evasion from the host's immune system. One such sortase, SrtA, recognizes and processes the sequence, Leu-Pro-X-Thr-Gly motif in vitro. Bioinformatics analyses predict SrtA may recognize LPXTG variants as well as a 6th amino acid. Another family of sortases, subfamily-3, is also predicted to process similar recognition motifs. We propose to determine the substrate specificity of these sortases to understand in vivo recognition. We will also use NMR spectroscopy to solve the structures of the sortase-substrate complexes. Results from this project will afford details on how these transpeptidases function and will identify residues participating in recognition. This work will complement ongoing sortase inhibitor studies.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31GM075564-03
Application #
7277275
Study Section
Minority Programs Review Committee (MPRC)
Program Officer
Toliver, Adolphus
Project Start
2005-09-01
Project End
2010-08-31
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
3
Fiscal Year
2007
Total Cost
$29,588
Indirect Cost
Name
University of California Los Angeles
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Villareal, Valerie A; Spirig, Thomas; Robson, Scott A et al. (2011) Transient weak protein-protein complexes transfer heme across the cell wall of Staphylococcus aureus. J Am Chem Soc 133:14176-9
Robson, Scott A; Peterson, Robert; Bouchard, Louis-S et al. (2010) A heteronuclear zero quantum coherence Nz-exchange experiment that resolves resonance overlap and its application to measure the rates of heme binding to the IsdC protein. J Am Chem Soc 132:9522-3
Ramey, Jordan D; Villareal, Valerie A; Ng, Charles et al. (2010) Anthrax toxin receptor 1/tumor endothelial marker 8: mutation of conserved inserted domain residues overrides cytosolic control of protective antigen binding. Biochemistry 49:7403-10
Suree, Nuttee; Liew, Chu Kong; Villareal, Valerie A et al. (2009) The structure of the Staphylococcus aureus sortase-substrate complex reveals how the universally conserved LPXTG sorting signal is recognized. J Biol Chem 284:24465-77
Villareal, Valerie A; Pilpa, Rosemarie M; Robson, Scott A et al. (2008) The IsdC protein from Staphylococcus aureus uses a flexible binding pocket to capture heme. J Biol Chem 283:31591-600