Summary information and primary citation
- PDB-id
-
8mht;
DSSR-derived features in text and
JSON formats
- Class
- transferase-DNA
- Method
- X-ray (2.76 Å)
- Summary
- Cytosine-specific methyltransferase hhai-DNA
complex
- Reference
-
O'Gara M, Horton JR, Roberts RJ, Cheng X (1998):
"Structures
of HhaI methyltransferase complexed with substrates
containing mismatches at the target base."
Nat.Struct.Biol., 5, 872-877.
doi: 10.1038/2312.
- Abstract
- Three structures have been determined for complexes
between HhaI methyltransferase (M.HhaI) and
oligonucleotides containing a G:A, G:U or G:AP (AP = abasic
or apurinic/apyrimidinic) mismatch at the target base pair.
The mismatched adenine, uracil and abasic site are all
flipped out of the DNA helix and located in the enzyme's
active-site pocket, adopting the same conformation as in
the flipped-out normal substrate. These results,
particularly the flipped-out abasic deoxyribose sugar,
provide insight into the mechanism of base flipping. If the
process involves the protein pushing the base out of the
helix, then the push must take place not on the base, but
rather on the sugar-phosphate backbone. Thus rotation of
the DNA backbone is probably the key to base flipping.
