Zinc- and iron-dependent cytosolic metallo-beta-lactamase domain proteins exhibit similar zinc-binding affinities, independent of an atypical glutamate at the metal-binding site.

ABSTRACT: ZiPD (zinc phosphodiesterase; synonyms are ElaC, ecoZ, RNaseZ and 3' tRNase) and the iron-dependent redox enzyme FlRd (flavorubredoxin) from Escherichia coli represent prototypical cases of proteins sharing the metallo-beta-lactamase fold that require strict metal selectivity for catalytic activity, yet their metal selectivity has only been partially understood. In contrast with hydrolytic metallo-beta-lactamase proteins, iron-dependent FlRd-like enzymes have an atypical glutamate ligand, which replaces one otherwise conserved histidine ligand. X-ray absorption spectroscopy revealed that the FlRd metallo-beta-lactamase domain is capable of incorporating two zinc ions into the binuclear metal-binding site. Zinc dissociation constants, determined by isothermal titration calorimetry are simil

SUBMITTER: Schilling O 

PROVIDER: S-EPMC1134682 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature