Structural basis and evolution of redox regulation in plant adenosine-5'-phosphosulfate kinase.

ABSTRACT: Adenosine-5'-phosphosulfate (APS) kinase (APSK) catalyzes the phosphorylation of APS to 3'-phospho-APS (PAPS). In Arabidopsis thaliana, APSK is essential for reproductive viability and competes with APS reductase to partition sulfate between the primary and secondary branches of the sulfur assimilatory pathway; however, the biochemical regulation of APSK is poorly understood. The 1.8-Å resolution crystal structure of APSR from A. thaliana (AtAPSK) in complex with β,γ-imidoadenosine-5'-triphosphate, Mg(2+), and APS provides a view of the Michaelis complex for this enzyme and reveals the presence of an intersubunit disulfide bond between Cys86 and Cys119. Functional analysis of AtAPSK demonstrates that reduction of Cys86-Cys119 resulted in a 17-fold higher k(cat)/K(m) and a 15-fold increase

SUBMITTER: Ravilious GE 

PROVIDER: S-EPMC3252903 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature