The coagulase of Staphylococcus aureus 8325‐4. Sequence analysis and virulence of site‐specific coagulase‐deficient mutants

Abstract

The sequence of the coagulase gene (coa) from Staphylococcus aureus strain 8325-4 is reported. The deduced amino acid sequence of the coagulase protein is compared with previously reported sequences of coagulases from strains 213 and BB. The secreted mature forms of coagulase proteins are composed of three distinct segments: (i) the N-terminal 150-270 residues, which are c. 50% identical, (ii) a central region with high (greater than 90%) residue identities, and (iii) a C-terminal region composed of repeated 27-amino-acid residue sequences. The variable N-terminal sequences are probably responsible for antigenic differences among coagulases of different serotype. The region of coagulase which binds to prothrombin and activates it to form staphylothrombin is also located in the N-terminal half of the protein. A site-specific substitution mutation in the coa gene, which abolished plasma clotting activity, was isolated by recombinational allele-replacement in strains 8325-4 and M60. The Coa- mutants did not show diminished virulence in subcutaneous and intramammary infections of mice. No evidence for a role for coagulase in virulence of toxigenic or nontoxigenic strains was obtained. This contradicts findings of several groups using Coa- mutants generated by chemical mutagenesis and suggests that the earlier results were obtained with strains that had suffered additional mutations in virulence-related genes.

Relatedness between the Coagulase Gene 3′‐End Region and Coagulase Serotypes among Staphylococcus aureus Strains

“…minal amino acid sequenceswould be responsible for antigenicdifferences among coagulases of different serotypes (14). The results of our phylogenetic analysis demonstrate that sequence analysis of the coagulase C-terminal region may be useful for discriminating among strains within a serotype.…”

Staphylococcus aureus-induced clotting of plasma is an immune evasion mechanism for persistence within the fibrin network

“…The S. aureus strains used in this study were 8325-4 (Novick, 1967) and its derivative SH1000 with a restored rsbU + gene which activates sigma factor B (s B ) (Horsburgh et al, 2002). The S. aureus mutant strain lacking coagulase (DCoa) was generated in the 8325-4 background as described previously (Phonimdaeng et al, 1990;McDevitt et al, 1992). S. aureus RN6390 is a laboratory strain related to 8325-4 with a truncated non-functional rsbU gene (Peng et al, 1988;Goerke et al, 2001).…”

Characterization of a strain of community-associated methicillin-resistant Staphylococcus aureus widely disseminated in the United States

“…The USA300-0114 isolates also contained an array of extracellular virulence factors, including numerous exoenzymes, such as serine protease (splA to splF) (58), zinc metalloproteinase aureolysin (aur) (3), coagulase (coa) (57), and lipase (geh) (41) genes. The V8 protease (sspA) (59), cysteine protease (sspB and sspC) (59), and hyaluronidase (hysA) (25) genes were detected, in addition to four enterotoxin genes.…”