The cell wall envelope of Gram-positive bacteria can be thought of as a microbial organelle with anchored surface proteins that require specific signals and targeting mechanism for their assembly. Previous work identified sortases, enzymes that recognize short peptide sequences within sorting signals of secreted proteins. Upon cleavage of a protein substrate immediately following a conserved threonine residue, sortases form a thioester acyl intermediate between the C-terminal carboxyl group of the substrate and their active site cysteine residue. This intermediate is subsequently resolved by the nucleophilic attack of an amino group, which completes the transpeptidation reaction and restores the active site of sortase. Four classes of sortases are distinguished on the basis of sequence homology and enzyme function. One of these, sortase A, cleaves all surface proteins harboring LPXTG sorting signals and tethers its products to the amino group of lipid II, the precursor of cell wall biosynthesis. In contrast, sortase D cleaves only the sorting signals of pilin subunits. By accepting the side chain amino group of lysine (K) within the YPKN motif of pilin precursors, sortase D assembles pili on the surface of Gram-positive bacteria. Bacillus cereus pili are formed from two subunits, the tip protein (BcpB) and the major pilin (BcpA), which generates the pilus shaft. Sortases A and D collaborate on the topic of pilus formation;their assembled product is immobilized in the cell wall and extends 0.3-1.5

Public Health Relevance

Gram-positive bacteria cause many different human diseases and the morbidity and mortality of these infections, largely due to the development of antibiotic resistance traits, continues to increase in the United States. By studying the molecular mechanisms whereby Gram-positive bacteria promote the anchoring and surface display of proteins that enable the pathogenesis of human infections, we aim to increase knowledge about infectious processes. By developing inhibitors that prevent the assembly of proteins in the bacterial envelope we aim to develop antiinfectives that may be useful for the treatment of human infections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI038897-19
Application #
8474677
Study Section
Prokaryotic Cell and Molecular Biology Study Section (PCMB)
Program Officer
Huntley, Clayton C
Project Start
1996-02-01
Project End
2014-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
19
Fiscal Year
2013
Total Cost
$355,555
Indirect Cost
$122,905
Name
University of Chicago
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Winstel, Volker; Missiakas, Dominique; Schneewind, Olaf (2018) Staphylococcus aureus targets the purine salvage pathway to kill phagocytes. Proc Natl Acad Sci U S A 115:6846-6851
Yu, Wenqi; Missiakas, Dominique; Schneewind, Olaf (2018) Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis. Elife 7:
Bobrovskyy, Maksym; Willing, Stephanie E; Schneewind, Olaf et al. (2018) EssH peptidoglycan hydrolase enables Staphylococcus aureus type VII secretion across the bacterial cell wall envelope. J Bacteriol :
Sun, Yan; Emolo, Carla; Holtfreter, Silva et al. (2018) Staphylococcal protein A contributes to persistent colonization of mice with Staphylococcus aureus. J Bacteriol :
Ohr, Ryan Jay; Anderson, Mark; Shi, Miaomiao et al. (2017) EssD, a Nuclease Effector of the Staphylococcus aureus ESS Pathway. J Bacteriol 199:
Anderson, Mark; Ohr, Ryan Jay; Aly, Khaled A et al. (2017) EssE Promotes Staphylococcus aureus ESS-Dependent Protein Secretion To Modify Host Immune Responses during Infection. J Bacteriol 199:
Nygaard, Tyler K; Kobayashi, Scott D; Freedman, Brett et al. (2016) Interaction of Staphylococci with Human B cells. PLoS One 11:e0164410
Missiakas, Dominique; Schneewind, Olaf (2016) Staphylococcus aureus vaccines: Deviating from the carol. J Exp Med 213:1645-53
Chan, Yvonne G Y; Frankel, Matthew B; Missiakas, Dominique et al. (2016) SagB Glucosaminidase Is a Determinant of Staphylococcus aureus Glycan Chain Length, Antibiotic Susceptibility, and Protein Secretion. J Bacteriol 198:1123-36
Kim, Hwan Keun; Falugi, Fabiana; Missiakas, Dominique M et al. (2016) Peptidoglycan-linked protein A promotes T cell-dependent antibody expansion during Staphylococcus aureus infection. Proc Natl Acad Sci U S A 113:5718-23

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