Document Actions
The C-terminal carboxy group of T7 RNA p ... gnesium ion-dependent catalysis
The C-terminal carboxy group of T7 RNA polymerase ensures efficient magnesium ion-dependent catalysis.
25
DNA and RNA polymerases use divalent metal ions for catalysis. Crystal structures of several polymerases reveal that two acidic residues are involved in coordinating two metal ions at the catalytic centre. Bacteriophage RNA polymerases contain a highly conserved C-terminus with the carboxylate positioned near the active site. We examined whether theC-terminal carboxy group of T7 RNA polymerase is important for magnesium ion-dependent catalysis. Introduction of a methyl ester or decarboxylation of the C-terminal carboxy group was achieved with an intein-based protein expression system and an elongation rate assay was developed to test the effects of the modifications. The results show that enzymes with a modified C-terminal carboxy group exhibit a magnesium ion-dependent decrease in catalytic activity.
Lykke-Andersen J, Christiansen J
Nucleic acids research
1998-12-15 00:00
26
24
5630-5
Bacteriophage T7,Catalysis,DNA-Directed RNA Polymerases,Escherichia coli,Magnesium,Viral Proteins,Viral Proteins,Magnesium,DNA-Directed RNA Polymerases
RNA Regulation Centre, Institute of Molecular Biology, University of Copenhagen, Solvgade 83 H,DK-1307 Copenhagen K, Denmark
Nucleic Acids Res.
0305-1048
gkb873
821
True
9837993
