title: Variation and association of fibronectin-binding protein genes fnbA and fnbB in Staphylococcus aureus Japanese isolates.
abstract: Fibronectin-binding proteins A and B (FnBPA and FnBPB) mediate adhesion of Staphylococcus aureus to fibrinogen, elastin and fibronectin. FnBPA and FnBPB are encoded by two closely linked genes, fnbA and fnbB, respectively. With the exception of the N-terminal regions, the amino acid sequences of FnBPA and FnBPB are highly conserved. To investigate the genetics and evolution of fnbA and fnbB, the most variable regions, which code for the 67th amino acids of the A through B regions (A67-B) of fnbA and fnbB, were focused upon. Eighty isolates of S. aureus in Japan were sequenced and 19 and 18 types in fnbA and fnbB, respectively, identified. Although the phylogeny of fnbA and fnbB were found to be quite different, each fnbA type connected with a specific fnbB type, indicating that fnbA and fnbB mutate independently, whereas the combination of both genes after recombination is stable. Hence those fnbA-fnbB combinations were defined as FnBP sequence types (FnSTs). Representative isolates of each FnST were assigned distinct STs by multilocus sequence typing, suggesting correspondence of FnST with genome lineage. Linkage disequilibrium (LD) analysis of the A67-B region revealed that subdomains N2, N3 and FnBR1 form a LD block in fnbA, whereas N2 and N3 form two independent LD blocks in fnbB. N2-N3 three-dimensional structural models indicated that not only the variable amino acid residues, but also well-conserved amino acid residues between FnBPA and FnBPB, are located on the surface of the protein. These results highlight a molecular process of the FnBP that has evolved by mingled mutation and recombination with retention of functions.
authors.affiliation: Department of Health Sciences, Saitama Prefectural University,820, Sannomiya, Koshigaya-shi, Saitama 343-8540.
authors.forename: Miyo
authors.initials: M
authors.lastname: Murai
authors.affiliation: School of Biological Sciences, University of Nebraska-Lincoln, 243 Manter Hall, Lincoln, Nebraska 68588, USA.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Moriyama
authors.affiliation: Dairy Hygiene Research Division, National Institute of Animal Health, 4 Hitsujigaoka, Toyohira-ku, Sapporo, Hokkaido 062-0045.
authors.forename: Eiji
authors.initials: E
authors.lastname: Hata
authors.affiliation: Pathogen Genomics Center, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Takeuchi
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Amemura-Maekawa
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics*; D016000:Cluster Analysis; D019143:Evolution, Molecular; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007564:Japan; D008958:Models, Molecular; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D018829:Adhesins, Bacterial; C078635:fibronectin-binding proteins, bacterial
keywords: Staphylococcal aureus; fibronectin-binding protein; linkage disequilibrium; multilocus sequence typing