title: Infection-derived Enterococcus faecalis strains are enriched in esp, a gene encoding a novel surface protein.
abstract: We report the identification of a new cell wall-associated protein of Enterococcus faecalis. Studies on the distribution of the gene encoding this novel surface protein, Esp, reveal a significant (P < 0.001) enrichment in infection-derived E. faecalis isolates. Interestingly, the esp gene was not identified in any of 34 clinical E. faecium isolates or in 4 other less pathogenic enterococcal species tested. Analysis of the structural gene among various E. faecalis isolates reveals the existence of alternate forms of expression of the Esp protein. The deduced primary structure of the Esp protein from strain MMH594, inferred to be 1,873 amino acids (aa) with a predicted mass of approximately 202 kDa, reveals a core region consisting of repeat units that make up 50% of the protein. Esp bears global organizational similarity to the Rib and C alpha proteins of group B streptococci. Identity among Esp, Rib, and C alpha proteins is strikingly localized to a stretch of 13 aa within repeats of similar length. The high degree of conservation of this 13-residue sequence suggests that it plays an important role in the natural selection for this trait among infection-derived E. faecalis and group B streptococcal isolates.
authors.affiliation: Department of Medicinal Chemistry and Pharmaceutics, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA.
authors.forename: V
authors.initials: V
authors.lastname: Shankar
authors.forename: A S
authors.initials: AS
authors.lastname: Baghdayan
authors.forename: M M
authors.initials: MM
authors.lastname: Huycke
authors.forename: G
authors.initials: G
authors.lastname: Lindahl
authors.forename: M S
authors.initials: MS
authors.lastname: Gilmore
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000737:chemistry; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002999:Clone Cells; D017124:Conserved Sequence; D013293:Enterococcus faecalis / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D014644:Genetic Variation; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D020080:Tandem Repeat Sequences
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D008565:Membrane Proteins; C081277:Rib protein, Streptococcus agalactiae; C116707:enterococcal surface protein, esp; C077961:alpha C protein, group B streptococci