2p1d

File:2p1d.gif

Crystal structure of dengue methyltransferase in complex with GTP and S-Adenosyl-L-homocysteine

Overview

Viruses represent an attractive system with which to study the molecular basis of mRNA capping and its relation to the RNA transcription machinery. The RNA-dependent RNA polymerase NS5 of flaviviruses presents a characteristic motif of S-adenosyl-L-methionine-dependent methyltransferases at its N-terminus, and polymerase motifs at its C-terminus. The crystal structure of an N-terminal fragment of Dengue virus type 2 NS5 is reported at 2.4 A resolution. We show that this NS5 domain includes a typical methyltransferase core and exhibits a (nucleoside-2'-O-)-methyltransferase activity on capped RNA. The structure of a ternary complex comprising S-adenosyl-L-homocysteine and a guanosine triphosphate (GTP) analogue shows that 54 amino acids N-terminal to the core provide a novel GTP-binding site that selects guanine using a previously unreported mechanism. Binding studies using GTP- and RNA cap-analogues, as well as the spatial arrangement of the methyltransferase active site relative to the GTP-binding site, suggest that the latter is a specific cap-binding site. As RNA capping is an essential viral function, these results provide a structural basis for the rational design of drugs against the emerging flaviviruses.

About this Structure

2P1D is a Single protein structure of sequence from Dengue virus 2. Full crystallographic information is available from OCA.

Reference

An RNA cap (nucleoside-2'-O-)-methyltransferase in the flavivirus RNA polymerase NS5: crystal structure and functional characterization., Egloff MP, Benarroch D, Selisko B, Romette JL, Canard B, EMBO J. 2002 Jun 3;21(11):2757-68. PMID:12032088 Page seeded by OCA on Sun May 4 12:08:01 2008

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