Dataset Information


Functional characterization of a 48 kDa Trypanosoma brucei cap 2 RNA methyltransferase.

ABSTRACT: Kinetoplastid mRNAs possess a unique hypermethylated cap 4 structure derived from the standard m7GpppN cap structure, with 2'-O methylations on the first four ribose sugars and additional base methylations on the first adenine and the fourth uracil. While the enzymes responsible for m7GpppN cap 0 formations has been characterized in Trypanosoma brucei, the mechanism of cap 4 methylation and the role of the hypermethylated structure remain unclear. Here, we describe the characterization of a 48 kDa T.brucei 2'-O nucleoside methyltransferase (TbCom1). Recombinant TbCom1 transfers the methyl group from S-adenosylmethionine (AdoMet) to the 2'-OH of the second nucleoside of m7GpppNpNp-RNA to form m7GpppNpNmp-RNA. TbCom1 is also capable of converting cap 1 RNA to cap 2 RNA. The methyl transfer reaction is dependent on the m7GpppN cap, as the enzyme does not form a stable interaction with GpppN-terminated RNA. Mutational analysis establishes that the TbCom1 and vaccinia virus VP39 methyltransferases share mechanistic similarities in AdoMet- and cap-recognition. Two aromatic residues, Tyr18 and Tyr187, may participate in base-stacking interactions with the guanine ring of the cap, as the removal of each of these aromatic side-chains abolishes cap-specific RNA-binding.


PROVIDER: S-EPMC1636459 | BioStudies | 2006-01-01

REPOSITORIES: biostudies

Similar Datasets

2006-01-01 | S-EPMC1383586 | BioStudies
2007-01-01 | S-EPMC3650844 | BioStudies
2020-01-01 | S-EPMC7004131 | BioStudies
2015-01-01 | S-EPMC4288156 | BioStudies
2019-01-01 | S-EPMC6847653 | BioStudies
2010-01-01 | S-EPMC2952261 | BioStudies
1000-01-01 | S-EPMC1061643 | BioStudies
2007-01-01 | S-EPMC1952150 | BioStudies
2020-01-01 | S-EPMC7038993 | BioStudies
2010-01-01 | S-EPMC2858705 | BioStudies