Arresting the Catalytic Arginine in Chlorite Dismutases: Impact on Heme Coordination, Thermal Stability, and Catalysis.

ABSTRACT: Chlorite dismutases (Clds) are heme b-containing oxidoreductases that can decompose chlorite to chloride and molecular oxygen. They are divided in two clades that differ in oligomerization, subunit architecture, and the hydrogen-bonding network of the distal catalytic arginine, which is proposed to switch between two conformations during turnover. To understand the impact of the conformational dynamics of this basic amino acid on heme coordination, structure, and catalysis, Cld from Cyanothece sp. PCC7425 was used as a model enzyme. As typical for a clade 2 Cld, its distal arginine 127 is hydrogen-bonded to glutamine 74. The latter has been exchanged with either glutamate (Q74E) to arrest R127 in a salt bridge or valine (Q74V) that mirrors the setting in clade 1 Clds. We pres

SUBMITTER: Schmidt D 

PROVIDER: S-EPMC7931450 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature