Species-specific cell wall binding affinity of the S-layer proteins of mosquitocidal bacterium Bacillus sphaericus C3-41.
The binding affinities and specificities of six truncated S-layer homology domain (SLH) polypeptides of mosquitocidal Bacillus sphaericus strain C3-41 with the purified cell wall sacculi have been assayed. The results indicated that the SLH polypeptide comprised of amino acids 31 to 210 was responsible for anchoring the S-layer subunits to the rigid cell wall layer via a distinct type of secondary cell wall polymer and that a motif of the recombinant SLH polypeptide comprising amino acids 152 to 210 (rSLH(152-210)) was essential for the stable binding of the S-layer with the bacterial cell walls. The quantitative assays revealed that the K(D) (equilibrium dissociation constant) values of rSLH(152-210) and rSLH(31-210) with purified cell wall sacculi were 1.11 x 10(-6) M and 1.40 x 10(-6) M, respectively. The qualitative assays demonstrated that the SLH domain of strain C3-41 could bind only to the cell walls or the cells treated with 5 M guanidinium hydrochloride of both toxic and nontoxic B. sphaericus strains but not to those from other bacteria, indicating the species-specific binding of the SLH polypeptide of B. sphaericus with bacterial cell walls.
Li
Jia
J
Wuhan Institute of Virology, Chinese Academy of Sciences, China.
Hu
Xiaomin
X
Yan
Jianpin
J
Yuan
Zhiming
Z
D000595:Amino Acid Sequence; D001407:Bacillus / Q000737:chemistry*; D002473:Cell Wall / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017433:Protein Structure, Secondary
D008562:Membrane Glycoproteins; C055764:S-layer proteins