Mechanistic insights into the manganese-dependent phosphodiesterase activity of yeast Dbr1 with bis-p-nitrophenylphosphate and branched RNA substrates.

ABSTRACT: Saccharomyces cerevisiae Dbr1 is a manganese-dependent RNA debranching enzyme that cleaves the 2'-5' phosphodiester bond of the lariat introns formed during pre-mRNA splicing. Dbr1 is a member of the binuclear metallophosphoesterase enzyme superfamily. We showed previously via alanine scanning that RNA debranching in vivo and in vitro depends on conserved active site residues His13, Asp40, Asn85, His86, His179, His231, and His233. Here, by extending the alanine scan, we added Cys11 to the ensemble of essential active site components. We report that Dbr1 has a vigorous manganese-dependent phosphodiesterase activity with the non-RNA substrate bis-p-nitrophenylphosphate. Whereas RNA debranching requires His86, bis-p-nitrophenylphosphatase activity does not. We interpret these and other struct

SUBMITTER: Schwer B 

PROVIDER: S-EPMC5113202 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature