title: Expression in Escherichia coli and sequence analysis of the listeriolysin O determinant of Listeria monocytogenes.
abstract: To evaluate the role of hemolysin production in the virulence of Listeria monocytogenes, we have undertaken the analysis of the chromosomal region containing hlyA, the gene coding for listeriolysin O. A recombinant cosmid, conferring a hemolytic phenotype to Escherichia coli, was shown to express listeriolysin O, by immunoblotting with a specific antiserum against listeriolysin O. The presence of hlyA on the cosmid was demonstrated by DNA hybridization with a probe previously shown to contain part of hlyA. The complete nucleotide sequence of hlyA has been determined. The deduced protein sequence reveals the presence of a putative 25-amino-acid signal sequence: the secreted form of listeriolysin O would have 504 amino acids, in agreement with the molecular weight of purified listeriolysin O (58,000). The protein sequence is highly homologous to those of streptolysin O and pneumolysin. A peptide of 11 amino acids conserved in the three proteins contains the unique cysteine known to be essential for lytic activity. By DNA-DNA hybridization, the listeriolysin O gene was detected in all L. monocytogenes strains tested, even in the nonhemolytic type strain. The gene was absent in other species of the genus Listeria.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins / Q000235:genetics*; D008089:Listeria monocytogenes / Q000235:genetics*; D008969:Molecular Sequence Data; D013045:Species Specificity; D013301:Streptolysins / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae; C025964:streptolysin O; C038705:hlyA protein, Listeria monocytogenes