9mht
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(New page: 200px<br /><applet load="9mht" size="450" color="white" frame="true" align="right" spinBox="true" caption="9mht, resolution 2.39Å" /> '''CYTOSINE-SPECIFIC ME...)
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Revision as of 10:50, 20 November 2007
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CYTOSINE-SPECIFIC METHYLTRANSFERASE HHAI/DNA COMPLEX
Overview
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.
About this Structure
9MHT is a Single protein structure of sequence from Haemophilus haemolyticus with SAH as ligand. Active as Deleted entry, with EC number 2.1.1.73 Full crystallographic information is available from OCA.
Reference
Structures of HhaI methyltransferase complexed with substrates containing mismatches at the target base., O'Gara M, Horton JR, Roberts RJ, Cheng X, Nat Struct Biol. 1998 Oct;5(10):872-7. PMID:9783745
Page seeded by OCA on Tue Nov 20 12:57:18 2007
