A role for Trigger Factor and an Rgg-like regulator in the transcription, secretion and processing of the cysteine proteinase of Streptococcus pyogenes

• Published in: The EMBO journal 1998-11, Vol.17 (21), p.6263-6275
• Main Authors: Lyon, William R., Gibson, Carmela M., Caparon, Michael G.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacterial Proteins - metabolism; Cloning, Molecular; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - metabolism; DNA Transposable Elements - genetics; DNA-Binding Proteins; FK506; Gene Expression Regulation, Bacterial - genetics; Gene Expression Regulation, Enzymologic - genetics; Molecular Sequence Data; Mutagenesis, Insertional - genetics; peptidyl-prolyl isomerase; Peptidylprolyl Isomerase - metabolism; RNA, Messenger - genetics; ropA; ropB; Sequence Analysis, DNA; Sequence Homology, Amino Acid; SpeB; Streptococcus pyogenes - enzymology; Streptococcus pyogenes - genetics; Trans-Activators; Transcription Factors - genetics; Transcription, Genetic - genetics
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1093/emboj/17.21.6263

The ability of numerous microorganisms to cause disease relies upon the highly regulated expression of secreted proteinases. In this study, mutagenesis with a novel derivative of Tn 4001 was used to identify genes required for the expression of the secreted cysteine proteinase (SCP) of the pathogenic Gram‐positive bacterium Streptococcus pyogenes . Designated as Rop loci (regulation of proteinase), ropB is a rgg ‐like transcriptional activator required for transcription of the gene which encodes the proteinase. In contrast, ropA contributes post‐transcriptionally to the secretion and processing of SCP and encodes a homologue of Trigger Factor, a peptidyl‐prolyl isomerase and putative chaparone which is highly conserved in most bacterial species, but of unknown function. Analysis of additional ropA mutants demonstrated that RopA acts both to assist in targeting SCP to the secretory pathway and to promote the ability of the proprotein to establish an active conformation upon secretion. This latter function was dependent upon the peptidyl‐prolyl isomerase domain of RopA and mutants that lacked this domain exhibited a bipartite deficiency manifested as a kinetic defect in autologous processing of the proprotein to the mature proteinase, and as a catalytic defect in the mature proteinase. These results provide insight into the function of Trigger Factor, the regulation of proteinase activity and the mechanism of secretion in Gram‐positive bacteria.