Open AccessSerratia marcescens forms a new type of cytolysin
Author(s) -
Braun Volkmar,
Hobbie Silke,
Ondraczek Roland
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb14056.x
Subject(s) - cytolysin , hemolysin , serratia , serratia marcescens , secretion , microbiology and biotechnology , bacterial outer membrane , biology , biochemistry , escherichia coli , bacteria , virulence , gene , pseudomonas , genetics
Most Serratin marcescens strains produce a new type of cytolysin (hemolysin) which is also found in other Serratin species. The hemolytic polypeptide ShlA ( M r , 162 101) is secreted across the outer membrane through the help of the ShlB protein which also involves conversion of an inactive precursor in an hemolytically active form. Both proteins are synthesized with signal sequences which are released during export across the cytoplasmic membrane. Mutants expressing inactive ShlB derivatives are impaired in activation and secretion suggesting a tight coupling between both processes. The region of ShlA for activation and secretion is confined to the N‐terminal 16% of the polypeptide which contains the sequence NPNG which is also found in the Proteus hemolysin, the Bordetella pertussis filamentous hemagglutinin and two highly expressed outer membrane proteins of Haemophilus influenzae Substitution of the first asparagine (N) residue by isoleucine converts the Serratia hemolysin into an inactive secretion incompetent form. It is concluded that this region is recognized by ShlB for activation and secretion of ShlA. The Serratia hemolysin forms defined pores in erythrocyte membranes.