2a8k
From Proteopedia
Structural and Mutational Studies of the Catalytic Domain of Colicin E5a tRNA-Specific Ribonuclease
Overview
Colicin E5 specifically cleaves four tRNAs in Escherichia coli that contain the modified nucleotide queuosine (Q) at the wobble position, thereby preventing protein synthesis and ultimately resulting in cell death. Here, the crystal structure of the catalytic domain of colicin E5 (E5-CRD) from E. coli was determined at 1.5 A resolution. Unexpectedly, E5-CRD adopts a core folding with a four-stranded beta-sheet packed against an alpha-helix, seen in the well-studied ribonuclease T1 despite a lack of sequence similarity. Beyond the core catalytic domain, an N-terminal helix, a C-terminal beta-strand and loop, and an extended internal loop constitute an RNA binding cleft. Mutational analysis identified five amino acids that were important for tRNA substrate binding and cleavage by E5-CRD. The structure, together with the mutational study, allows us to propose a model of colicin E5-tRNA interactions, suggesting the molecular basis of tRNA substrate recognition and the mechanism of tRNA cleavage by colicin E5.
About this Structure
2A8K is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structural and mutational studies of the catalytic domain of colicin E5: a tRNA-specific ribonuclease., Lin YL, Elias Y, Huang RH, Biochemistry. 2005 Aug 9;44(31):10494-500. PMID:16060658 Page seeded by OCA on Sat May 3 18:44:51 2008
