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Biochem Biophys Res Commun. 2002 Mar 8;291(4):932-8.

Mutational analysis of a mammalian reovirus mRNA capping enzyme.

Author information

1
Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA. cindy_luongo@microbio.uab.edu

Abstract

The amino-terminal 42-kDa region of the 144-kDa mammalian reovirus lambda 2 protein is a guanylyltransferase. It catalyzes the transfer of GMP from GTP to the 5' end of 5' -diphosphorylated mRNA via a phosphoamide with Lys-190. This amino acid is located at the base of a deep cleft. Based on sequence comparisons, the Kx[V/L/I]S motif is present in all known and proposed guanylyltransferases of the family Reoviridae. The requirement for this conserved sequence and other regions of the enzyme was analyzed by site-directed mutagenesis. Based on the enzymatic activity of the mutants, Lys-190 and Asp-191 are the only amino acids of the (190)KDLS sequence that are necessary for enzymatic activity. Since Asp-191 has its side chain oriented away from the cleft, most likely it plays an indirect role in forming a functional guanylyltransferase.

PMID:
11866455
DOI:
10.1006/bbrc.2002.6520
[Indexed for MEDLINE]

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