2yy8
Crystal structure of archaeal tRNA-methylase for position 56 (aTrm56) from Pyrococcus horikoshii, complexed with S-adenosyl-L-methionine
OverviewOverview
The conserved cytidine residue at position 56 of tRNA contributes to the maintenance of the L-shaped tertiary structure. aTrm56 catalyzes the 2'-O-methylation of the cytidine residue in archaeal tRNA, using S-adenosyl-L-methionine. Based on the amino acid sequence, aTrm56 is the most distant member of the SpoU family. Here, we determined the crystal structure of Pyrococcus horikoshii aTrm56 complexed with S-adenosyl-L-methionine at 2.48 A resolution. aTrm56 consists of the SPOUT domain, which contains the characteristic deep trefoil knot, and a unique C-terminal beta-hairpin. aTrm56 forms a dimer. The S-adenosyl-L-methionine binding and dimerization of aTrm56 were similar to those of the other SpoU members. A structure-based sequence alignment revealed that aTrm56 conserves only motif II, among the four signature motifs. However, an essential Arg16 residue is located at a novel position within motif I. Biochemical assays showed that aTrm56 prefers the L-shaped tRNA to the lambda form as its substrate.
About this StructureAbout this Structure
2YY8 is a Single protein structure of sequence from Pyrococcus horikoshii. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure and mutational study of a unique SpoU family archaeal methylase that forms 2'-O-methylcytidine at position 56 of tRNA., Kuratani M, Bessho Y, Nishimoto M, Grosjean H, Yokoyama S, J Mol Biol. 2008 Jan 25;375(4):1064-75. Epub 2007 Nov 17. PMID:18068186 Page seeded by OCA on Sun May 4 19:41:06 2008