Structure of the guanylyltransferase domain of human mRNA capping enzyme.

ABSTRACT: The enzyme guanylyltransferase (GTase) plays a central role in the three-step catalytic process of adding an (m7)GpppN cap cotranscriptionally to nascent mRNA (pre-mRNAs). The 5'-mRNA capping process is functionally and evolutionarily conserved from unicellular organisms to human. However, the GTases from viruses and yeast have low amino acid sequence identity (∼25%) with GTases from mammals that, in contrast, are highly conserved (∼98%). We have defined by limited proteolysis of human capping enzyme residues 229-567 as comprising the minimum enzymatically active human GTase (hGTase) domain and have determined the structure by X-ray crystallography. Seven related conformational states of hGTase exist in the crystal. The GTP-binding site is evolutionarily and structurally conserved. The pos

SUBMITTER: Chu C 

PROVIDER: S-EPMC3121809 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature