CATH Classification

Domain Context

CATH Clusters

Superfamily Aldolase class I
Functional Family Dual-specificity RNA methyltransferase RlmN

Enzyme Information

2.1.1.192
23S rRNA (adenine(2503)-C(2))-methyltransferase.
based on mapping to UniProt P36979
(1) 2 S-adenosyl-L-methionine + adenine(2503) in 23S rRNA + 2 reduced [2Fe-2S] ferredoxin = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + 2-methyladenine(2503) in 23S rRNA + 2 oxidized [2Fe- 2S] ferredoxin. (2) 2 S-adenosyl-L-methionine + adenine(37) in tRNA + 2 reduced [2Fe-2S] ferredoxin = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + 2-methyladenine(37) in tRNA + 2 oxidized [2Fe-2S] ferredoxin.
-!- This enzyme is a member of the 'AdoMet radical' (radical SAM) family. -!- S-adenosyl-L-methionine acts as both a radical generator and as the source of the appended methyl group. -!- RlmN first transfers an CH(2) group to a conserved cysteine (Cys(355) in Escherichia coli), the generated radical from a second S-adenosyl- L-methionine then attacks the methyl group, exctracting a hydrogen. -!- The formed radical forms a covalent intermediate with the adenine group of the tRNA. -!- RlmN is an endogenous enzyme used by the cell to refine functions of the ribosome in protein synthesis. -!- The enzyme methylates adenosine by a radical mechanism with CH(2) from the S-adenosyl-L-methionine and retention of the hydrogen at C-2 of adenosine(2503) of 23S rRNA. -!- It will also methylate 8-methyladenosine(2503) of 23S rRNA (cf. EC 2.1.1.224).

UniProtKB Entries (1)

P36979
RLMN_ECOLI
Escherichia coli K-12
Dual-specificity RNA methyltransferase RlmN

PDB Structure

PDB 5HR7
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Crystallographic capture of a radical S-adenosylmethionine enzyme in the act of modifying tRNA.
Schwalm, E.L., Grove, T.L., Booker, S.J., Boal, A.K.
Science