1eam
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VACCINIA METHYLTRANSFERASE VP39 MUTANT (EC: 2.7.7.19)
OverviewOverview
We have determined, by high resolution x-ray analysis, 10 structures, comprising the mRNA cap-specific methyltransferase VP39 or specific, mutants thereof in the presence of methylated nucleobase analogs, (N1-methyladenine, N3-methyladenine, N1-methylcytosine, N3-methylcytosine), and their unmethylated counterparts, or nucleoside N7-methylguanosine., Together with solution affinity studies and previous crystallographic data, for N7-methylguanosine and its phosphorylated derivatives, these data, demonstrate that only methylated, positively charged bases are bound, indicating that their enhanced stacking with two aromatic side chains of, VP39 (Tyr 22 and Phe 180) plays a dominant role in cap recognition. Four, key features characterize this stacking interaction: (i) near perfect, parallel alignment between the sandwiched methylated bases and aromatic, side chains, (ii) substantial areas of overlap in the two-stacked rings, (iii) a 3.4-A interplanar spacing within the overlapping region, and (iv), positive charge in the heterocyclic nucleobase.
About this StructureAbout this Structure
1EAM is a Single protein structure of sequence from Vaccinia virus with SAH as ligand. Active as Polynucleotide adenylyltransferase, with EC number 2.7.7.19 Full crystallographic information is available from OCA.
ReferenceReference
mRNA cap recognition: dominant role of enhanced stacking interactions between methylated bases and protein aromatic side chains., Hu G, Gershon PD, Hodel AE, Quiocho FA, Proc Natl Acad Sci U S A. 1999 Jun 22;96(13):7149-54. PMID:10377383
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