The S-layer homology domain as a means for anchoring heterologous proteinson the cell surface of Bacillus anthracis

Bacillus anthracis synthesizes two S-layer proteins, each containing three S-laver homology (SLH) motifs towards their amino-terminus. In vitro experi ments suggested that the three motifs of-each protein were organized as a s tructural domain sufficient to bind purified cell walls. Chimeric genes enc oding the SLH domains fused to the levansucrase of Bacillurs subtilis were constructed and integrated on the chromosome. Cell fractionation and electr on microscopy studies showed that both heterologous polypeptides were targe ted to the cell surface. In addition, surface-exposed levansucrase retained its enzymatic and antigenic properties. Preliminary, results concerning ap plications of this work are presented.