ClpXP degrades SsrA-tagged proteins in Streptococcus pneumoniae.
Bacterial proteins that are abnormally truncated due to incomplete mRNA or the presence of rare codons are extended by an SsrA tag during ribosome rescue in a trans-translation process important for maintaining protein quality. In Escherichia coli, the SsrA-tagged proteins become the target of the Tsp, Lon, FtsH, ClpXP, and ClpAP proteases. Here we show that degradation of model SsrA-tagged proteins in Streptococcus pneumoniae depends primarily or exclusively on ClpXP in vivo. In addition, we show the E. coli SsrA tag is also a target of S. pneumoniae ClpXP in vivo, even though the N-terminal portions of the tags differ significantly between the two species, suggesting there may be no adaptor protein for SsrA in S. pneumoniae.
Ahlawat
Sarita
S
LMB Room 4150, 900 South Ashland Ave., Chicago, IL 60607, USA.
Morrison
Donald A
DA
D001426:Bacterial Proteins / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D023061:Gene Order; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism*; D012329:RNA, Bacterial / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000378:metabolism*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; C096222:tmRNA; D010447:Peptide Hydrolases; C483573:ClpXP protease, E coli; D049071:Endopeptidase Clp