Format

Send to

Choose Destination
J Bacteriol. 2015 Oct;197(19):3216-27. doi: 10.1128/JB.00492-15. Epub 2015 Jul 27.

Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly.

Author information

1
Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA.
2
Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA oschnee@bsd.uchicago.edu.

Abstract

Bacillus anthracis vegetative forms assemble an S-layer comprised of two S-layer proteins, Sap and EA1. A hallmark of S-layer proteins are their C-terminal crystallization domains, which assemble into a crystalline lattice once these polypeptides are deposited on the bacterial surface via association between their N-terminal S-layer homology domains and the secondary cell wall polysaccharide. Here we show that slaQ, encoding a small cytoplasmic protein conserved among pathogenic bacilli elaborating S-layers, is required for the efficient secretion and assembly of Sap and EA1. S-layer protein precursors cosediment with SlaQ, and SlaQ appears to facilitate Sap assembly. Purified SlaQ polymerizes and when mixed with purified Sap promotes the in vitro formation of tubular S-layer structures. A model is discussed whereby SlaQ, in conjunction with S-layer secretion factors SecA2 and SlaP, promotes localized secretion and S-layer assembly in B. anthracis.

IMPORTANCE:

S-layer proteins are endowed with the propensity for self-assembly into crystalline arrays. Factors promoting S-layer protein assembly have heretofore not been reported. We identified Bacillus anthracis SlaQ, a small cytoplasmic protein that facilitates S-layer protein assembly in vivo and in vitro.

PMID:
26216847
PMCID:
PMC4560277
DOI:
10.1128/JB.00492-15
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center