TRNA recognition by a bacterial tRNA Xm32 modification enzyme from the SPOUT methyltransferase superfamily.

ABSTRACT: TrmJ proteins from the SPOUT methyltransferase superfamily are tRNA Xm32 modification enzymes that occur in bacteria and archaea. Unlike archaeal TrmJ, bacterial TrmJ require full-length tRNA molecules as substrates. It remains unknown how bacterial TrmJs recognize substrate tRNAs and specifically catalyze a 2'-O modification at ribose 32. Herein, we demonstrate that all six Escherichia coli (Ec) tRNAs with 2'-O-methylated nucleosides at position 32 are substrates of EcTrmJ, and we show that the elbow region of tRNA, but not the amino acid acceptor stem, is needed for the methylation reaction. Our crystallographic study reveals that full-length EcTrmJ forms an unusual dimer in the asymmetric unit, with both the catalytic SPOUT domain and C-terminal extension forming separate dimeric associ

SUBMITTER: Liu RJ 

PROVIDER: S-EPMC4551947 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature