Divalent metal-dependent catalysis and cleavage specificity of CSP41, a chloroplast endoribonuclease belonging to the short chain dehydrogenase/reductase superfamily.

ABSTRACT: CSP41 is a ubiquitous chloroplast endoribonuclease belonging to the short chain dehydrogenase/reductase (SDR) superfamily. To help elucidate the role of CSP41 in chloroplast gene regulation, the mechanisms that determine its substrate recognition and catalytic activity were investigated. A divalent metal is required for catalysis, most probably to provide a nucleophile for cleavage 5' to the phosphodiester bond, and may also participate in cleavage site selection. This requirement distinguishes CSP41 from other Rossman fold-containing proteins from the SDR superfamily, including several RNA-binding proteins and endonucleases. CSP41 is active only in the presence of MgCl2 and CaCl2. Although Mg2+- and Ca2+-activated CSP41 cleave at identical sites in the single-stranded regions of a stem-lo

SUBMITTER: Bollenbach TJ 

PROVIDER: S-EPMC169913 | biostudies-literature | 2003 Aug

REPOSITORIES: biostudies-literature