Recognition of the RNA cap in the Wesselsbron virus NS5 methyltransferase domain: implications for RNA-capping mechanisms in Flavivirus
Articolo
Data di Pubblicazione:
2009
Citazione:
Recognition of the RNA cap in the Wesselsbron virus NS5 methyltransferase domain: implications for RNA-capping mechanisms in Flavivirus / M. Bollati, M. Milani, E. Mastrangelo, S. Ricagno, G. Tedeschi, S. Nonnis, E. Decroly, B. Selisko, X. de Lamballerie, B. Coutard, B. Canard, M. Bolognesi. - In: JOURNAL OF MOLECULAR BIOLOGY. - ISSN 0022-2836. - 385:1(2009), pp. 140-152.
Abstract:
The mRNA-capping process starts with the conversion of a 5V-triphosphate
end into a 5V-diphosphate by an RNA triphosphatase, followed by the
addition of a guanosine monophosphate unit in a 5V–5Vphosphodiester bond
by a guanylyltransferase. Methyltransferases are involved in the third step of
the process, transferring a methyl group from S-adenosyl-L-methionine to
N7-guanine (cap 0) and to the ribose 2VOH group (cap 1) of the first RNA
nucleotide; capping is essential for mRNA stability and proper replication.
In the genus Flavivirus, N7-methyltransferase and 2VO-methyltransferase
activities have been recently associated with the N-terminal domain of the
viral NS5 protein. In order to further characterize the series of enzymatic
reactions that support capping, we analyzed the crystal structures of
Wesselsbron virus methyltransferase in complex with the S-adenosyl-Lmethionine
cofactor, S-adenosyl-L-homocysteine (the product of the
methylation reaction), Sinefungin (a molecular analogue of the enzyme
cofactor), and three different cap analogues (GpppG, N7MeGpppG, and
N7MeGpppA). The structural results, together with those on other flaviviral
methyltransferases, show that the capped RNA analogues all bind to an
RNA high-affinity binding site. However, lack of specific interactions
between the enzyme and the first nucleotide of the RNA chain suggests the
requirement of a minimal number of nucleotides following the cap to
strengthen protein/RNA interaction. Our data also show that, following
incubation with guanosine triphosphate,Wesselsbron virus methyltransferase
displays a guanosine monophosphate molecule covalently bound to
residue Lys28, hinting at possible implications for the transfer of a guanine
group to ppRNA. The structures of theWesselsbron virus methyltransferase
complexes obtained are discussed in the context of a model for N7-
methyltransferase and 2VO-methyltransferase activities.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Flavivirus; guanylyltransferase; methyltransferase; RNA capping; viral enzyme structure
Elenco autori:
M. Bollati, M. Milani, E. Mastrangelo, S. Ricagno, G. Tedeschi, S. Nonnis, E. Decroly, B. Selisko, X. de Lamballerie, B. Coutard, B. Canard, M. Bolognesi
Link alla scheda completa: