HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (Papers in Press[PDF]) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Moody, K. L Articles by Bozue, J. A PubMed PubMed Citation Articles by Moody, K. L Articles by Bozue, J. A Agricola Articles by Moody, K. L Articles by Bozue, J. A

Processing, Assembly, and Localization of a Bacillus anthracis Spore Protein

¹ USAMRIID;
² Loyola University Medical Center;
³ United States Army Medical Research Institute of Infectious Diseases (USAMRIID)

All Bacillus spores are encased in macromolecular shells. One of these is a proteinacious shell called the coat that, in Bacillus subtilis, provides critical protective functions. The Bacillus anthracis spore is the infectious particle for the disease anthrax. Therefore, the coat is of particular interest because it may provide essential protective functions required for the appearance of anthrax. Here, we analyze a protein component of the spore outer layers that was previously designated as BxpA. Our data indicate that a significant amount of BxpA is located below the spore coat and associated with the cortex. By SDS-PAGE, BxpA migrates as a 9-kD species when extracted from Sterne strains spores, and as 11- and 14-kD species from Ames strain spores, even though it has predicted masses of 27-kD and 29-kD, respectively, in these two strains. We investigated the possibility that BxpA is subject to posttranslational processing as previously suggested. In B. subtilis, a subset of coat proteins is proteolyzed or crosslinked by the spore proteins YabG or Tgl, respectively. To investigate the possibility that similar processing occurs in B. anthracis, we generated mutations in the yabG or tgl genes in the Sterne and Ames strains and analyzed the consequences for BxpA assembly by SDS-PAGE. We found that in a tgl mutant of B. anthracis, the apparent mass of BxpA increased. This is consistent with the possibility that Tgl directs the crosslinking of BxpA into a form that normally does not enter the gel. Unexpectedly, the apparent mass of BxpA also increased in a yabG mutant, suggesting a relatively complex role for proteolysis in spore protein maturation in B. anthracis. These data reveal a previously unobserved event in spore protein maturation in B. anthracis. We speculate that proteolysis and crosslinking are ubiquitous spore assembly mechanisms throughout the genus Bacillus.

⁴ E-mail: joel.a.bozue{at}us.army.mil