Characterization of emb, a gene encoding the major adhesin of Streptococcus defectivus.
Streptococcus defectivus is one of the nutritionally variant streptococci, a class of viridans group streptococci first isolated from patients with endocarditis and otitis media. In previous studies, NVS-47, a clinical isolate of S. defectivus, was shown to bind to the extracellular matrix. A high-molecular-weight surface protein was identified and proposed to be responsible for mediating this binding. In the present study, the gene encoding this protein was identified by transposon mutagenesis and characterized. The gene (emb) was found to be larger than 14 kb and was partially sequenced. It encodes a protein containing at least 50 repeats of 77 amino acids predicted to assume an alternating coiled-coil conformation. The domain responsible for extracellular matrix binding was mapped to the N terminus of the protein. From sequence analysis, Emb is proposed to be the prototype of a new family of streptococcal fibrillar proteins.
Manganelli
R
R
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
van de Rijn
I
I
D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000378:metabolism; D001483:Base Sequence; D001666:Binding Sites, Antibody; D002460:Cell Line; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D004251:DNA Transposable Elements; D005109:Extracellular Matrix / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D013291:Streptococcus / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D004251:DNA Transposable Elements; D010446:Peptide Fragments; C116706:emb protein, Abiotrophia defectiva