Ribosomal protein S1 binds mRNA and tmRNA similarly but plays distinct roles in translation of these molecules.

ABSTRACT: Ribosomes stalled during protein synthesis can be rescued by tmRNA, which acts first as a tRNA and then as an mRNA to direct addition of a C-terminal degradation tag to the nascent polypeptide. Ribosomal protein S1 binds tmRNA, but its functional role in tmRNA-mediated tagging is uncertain. To probe interactions between S1 and tmRNA, truncated variants missing one or more of the six contiguous S1 domains were studied. The third S1 domain (R1) plays a critical role in binding tmRNA and mRNA but requires additional N- or C-terminal S1 domains. The binding of S1 and its fragments to tmRNA and mRNA is positively cooperative, and the essential role of the R1 domain may be to mediate protein-protein interactions. Overproduction of N-terminal fragments of S1 in Escherichia coli displaces endogeno

SUBMITTER: McGinness KE 

PROVIDER: S-EPMC518778 | biostudies-literature | 2004 Sep

REPOSITORIES: biostudies-literature