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Crystal structure of tRNA(m 1 G37)methyltransferase: insights into tRNA recognition
Author(s) -
Ahn Hyung Jun,
Kim HyeonWoo,
Yoon HyeJin,
Lee Byung II,
Suh Se Won,
Yang Jin Kuk
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg269
Subject(s) - transfer rna , biology , methyltransferase , genetics , t arm , computational biology , biochemistry , rna , dna , methylation , gene
tRNA(m 1 G37)methyltransferase (TrmD) catalyzes the transfer of a methyl group from S ‐adenosyl‐ L ‐ methionine (AdoMet) to G 37 within a subset of bacterial tRNA species, which have a G residue at the 36th position. The modified guanosine is adjacent to and 3′ of the anticodon and is essential for the maintenance of the correct reading frame during translation. Here we report four crystal structures of TrmD from Haemophilus influenzae , as binary complexes with either AdoMet or S ‐adenosyl‐ L ‐homocysteine (AdoHcy), as a ternary complex with AdoHcy and phosphate, and as an apo form. This first structure of TrmD indicates that it functions as a dimer. It also suggests the binding mode of G 36 G 37 in the active site of TrmD and the catalytic mechanism. The N‐terminal domain has a trefoil knot, in which AdoMet or AdoHcy is bound in a novel, bent conformation. The C‐terminal domain shows structural similarity to trp repressor. We propose a plausible model for the TrmD 2 –tRNA 2 complex, which provides insights into recognition of the general tRNA structure by TrmD.