A COLLAGEN-BINDING S-LAYER PROTEIN IN LACTOBACILLUS-CRISPATUS

Two S-layer-expressing strains, Lactobacillus crispatus JCM 5810 and L actobacillus acidophilus JCM 1132, were assessed for adherence to prot eins of the mammalian extracellular matrix. L. crispatus JCM 5810 adhe red efficiently to immobilized type IV and I collagens, laminin, and,, vith a lower affinity, to type V collagen and fibronectin. Strain JCM 1132 did not exhibit detectable adhesiveness. Within the fibronectin m olecule, JCM 5810 recognized the 120-kDa cell-binding fragment of the protein, while no bacterial adhesion to the aminoterminal 30-kDa or th e gelatin-binding 40-kDa fragment was detected. JCM 5810 but not JCM 1 132 also bound I-125-labelled soluble type IV collagen, and this bindi ng was efficiently inhibited by unlabelled type IV and I collagens and less efficiently by type V collagen, but not by laminin or fibronecti n. L. crispatus: JCM 5810 but not L. acidophilus JCM 1132 also adhered to Matrigel, a reconstituted basement membrane preparation from mouse sarcoma cells, as well as to the extracellular matrix prepared from h uman Intestine 407 cells. S-layers from both strains were extracted wi th 2 M guanidine hydrochloride; separated by electrophoresis, and tran sferred to nitrocellulose sheets. The S-layer protein from JCM 5810 bo und I-125-labelled type IV collagen, ,whereas no binding was seen with the S-layer protein from JCM 1132. Binding of I-125-collagen IV to th e JCM 5810 S-layer protein was effectively inhibited by unlabelled typ e I and IV collagens but not by type V collagen, laminin, or fibronect in. It was concluded that L. crispatus JCM 5810 has the capacity to ad here to human subintestinal extracellular matrix via a collagen-bindin g S-layer.