A general strategy for identification of S-layer genes in the Bacillus cereus group: molecular characterization of such a gene in Bacillus thuringiensis subsp galleriae NRRL 4045
S. Mesnage et al., A general strategy for identification of S-layer genes in the Bacillus cereus group: molecular characterization of such a gene in Bacillus thuringiensis subsp galleriae NRRL 4045, MICROBI-SGM, 147, 2001, pp. 1343-1351
Despite its possible role in virulence, there has been little molecular cha
racterization of members of the S-layer protein family of the Bacillus cere
us group. It is hypothesized that the components of the S-layers are likely
to display similar anchoring structures in Bacillus thuringiensis and Baci
llus anthracis. Based on inferred sequence similarities, a DNA fragment enc
oding the cell-wall-anchoring domain of an S-layer component of Bac. thurin
giensis subsp. galleriae NRRL 4045 was isolated. The complete gene was iden
tified and sequenced. An ORF of 2463 nt was identified, which was predicted
to encode a protein of 821 aa, SlpA. The mature SlpA protein (792 residues
) carries three S-layer homology (SLH) motifs towards its amino terminus, e
ach about 50 aa long. These motifs were sufficient to bind Bac. thuringiens
is and Bac. anthracis cell walls in vitro by interacting with peptidoglycan
-associated polymers, confirming a common wall-anchoring mechanism. The slp
A null-allele mutant was constructed and shown to possess no other abundant
surface protein. It is proposed that the method described in this paper co
uld be applied to the identification and deletion of any Bac. cereus S-laye
r gene and is of great value for the molecular and functional characterizat
ion of these genes.