Staphylococcus aureus is the causative agent for a wide range of human diseases, especially suppurative infections. S aureus is also the single most common cause of hospital acquired (nosocomial) infections in American hospitals today. Nosocomial infections are of extreme concern, because of the increased admittance of immunocompromised patients in American hospitals, particularly patients with AIDS. This problem is further aggravated by the occurrence of multiple drug resistances in S aureus, with few effective antibiotic regimens available. Recent hospital isolates of S aureus were resistant to all known antibiotics and the development of new targets for antibiotic therapy is therefore urgently needed. A variety of surface proteins is responsible for staphylococcal virulence, but the mechanism by which these proteins anchor to the surface is not understood. In this proposal it is shown that protein A, another surface protein, is anchored in the staphylococcal cell wall. The signal for cell wall anchoring is encoded in three C-terminal sequence elements of protein A: a LPXTGX sequence motif, a C-terminal hydrophobic domain, and a charged tail. These three sequence elements are conserved in more that 30 different surface proteins from different gram-positive species suggesting that these proteins may anchor in a similar manner. In this proposal, the sorting signal sufficient for cell wall anchoring of protein A will be characterized with mutant and hybrid proteins. The linkage between protein A and the staphylococcal peptidoglycan will be studied by direct methods of chemical analysis. Furthermore, mutagenesis experiments will screen for the genetic determinants responsible for cell wall sorting of protein A in S aureus. Cell wall anchoring of surface proteins may be specific for gram-positive bacteria and could therefore present a new target for antibiotic therapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29AI033985-03
Application #
2069049
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1993-04-01
Project End
1998-03-31
Budget Start
1995-04-01
Budget End
1996-03-31
Support Year
3
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Ton-That, H; Schneewind, O (1999) Anchor structure of staphylococcal surface proteins. IV. Inhibitors of the cell wall sorting reaction. J Biol Chem 274:24316-20
Lee, V T; Schneewind, O (1999) Type III secretion machines and the pathogenesis of enteric infections caused by Yersinia and Salmonella spp. Immunol Rev 168:241-55
Navarre, W W; Ton-That, H; Faull, K F et al. (1999) Multiple enzymatic activities of the murein hydrolase from staphylococcal phage phi11. Identification of a D-alanyl-glycine endopeptidase activity. J Biol Chem 274:15847-56
Navarre, W W; Schneewind, O (1999) Surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. Microbiol Mol Biol Rev 63:174-229
Navarre, W W; Ton-That, H; Faull, K F et al. (1998) Anchor structure of staphylococcal surface proteins. II. Cooh-terminal structure of muramidase and amidase-solubilized surface protein. J Biol Chem 273:29135-42
Baba, T; Schneewind, O (1998) Targeting of muralytic enzymes to the cell division site of Gram-positive bacteria: repeat domains direct autolysin to the equatorial surface ring of Staphylococcus aureus. EMBO J 17:4639-46
Lee, V T; Anderson, D M; Schneewind, O (1998) Targeting of Yersinia Yop proteins into the cytosol of HeLa cells: one-step translocation of YopE across bacterial and eukaryotic membranes is dependent on SycE chaperone. Mol Microbiol 28:593-601
Ton-That, H; Labischinski, H; Berger-Bachi, B et al. (1998) Anchor structure of staphylococcal surface proteins. III. Role of the FemA, FemB, and FemX factors in anchoring surface proteins to the bacterial cell wall. J Biol Chem 273:29143-9
Ton-That, H; Faull, K F; Schneewind, O (1997) Anchor structure of staphylococcal surface proteins. A branched peptide that links the carboxyl terminus of proteins to the cell wall. J Biol Chem 272:22285-92
Baba, T; Schneewind, O (1996) Target cell specificity of a bacteriocin molecule: a C-terminal signal directs lysostaphin to the cell wall of Staphylococcus aureus. EMBO J 15:4789-97

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