Summary information and primary citation
- PDB-id
-
2bh2;
SNAP-derived features in text and
JSON formats
- Class
- transferase
- Method
- X-ray (2.15 Å)
- Summary
- Crystal structure of e. coli 5-methyluridine
methyltransferase ruma in complex with ribosomal RNA
substrate and s-adenosylhomocysteine.
- Reference
-
Lee TT, Agarwalla S, Stroud RM (2005): "A Unique
RNA Fold in the Ruma-RNA-Cofactor Ternary Complex
Contributes to Substrate Selectivity and Enzymatic
Function." Cell(Cambridge,Mass.),
120, 599. doi: 10.1016/J.CELL.2004.12.037.
- Abstract
- A single base (U1939) within E. coli 23S ribosomal RNA
is methylated by its dedicated enzyme, RumA. The structure
of RumA/RNA/S-adenosylhomocysteine uncovers the mechanism
for achieving unique selectivity. The single-stranded
substrate is "refolded" on the enzyme into a compact
conformation with six key intra-RNA interactions. The RNA
substrate contributes directly to catalysis. In addition to
the target base, a second base is "flipped out" from the
core loop to stack against the adenine of the cofactor
S-adenosylhomocysteine. Nucleotides in permuted sequence
order are stacked into the site vacated by the everted
target U1939 and compensate for the energetic penalty of
base eversion. The 3' hairpin segment of the RNA binds
distal to the active site and provides binding energy that
contributes to enhanced catalytic efficiency. Active
collaboration of RNA in catalysis leads us to conclude that
RumA and its substrate RNA may reflect features from the
earliest RNA-protein era.
