Functional Analysis of Arabidopsis ATP Sulfurylases Essential for the Synthesis of Sulfur-Containing Compounds.

Abstract

In higher plants, sulfate taken up from the environment is converted to adenosine 5'-phosphosulfate (APS) by ATP sulfurylase. APS can be a substrate of sulfur reduction, or can be phosphorylated to yield 3'-phosphoadenosine 5'-phosphosulfate, a donor for sulfation of a range of metabolites. The Arabidopsis genome contains four ATP sulfurylase genes (ATPS1, ATPS2, ATPS3, ATPS4). Physiological function of each ATPS was analyzed in their knockout mutants. atps1, atps2 and atps3 exhibited lower levels of ATP sulfurylase activity than wild-type plants. Expression of ATPS-GFP fusion constructs in Arabidopsis plants suggested that ATPS1, ATPS3 and ATPS4 localized exclusively in chloroplasts whereas ATPS2 expressed in both cytosol and chloroplasts. In addition, cell type-specificities of ATPS were different from each other. It is suggested that each ATPS plays a specific role in the sulfur metabolism.