A complex iron-calcium cofactor catalyzing phosphotransfer chemistry

Abstract

Cofactors linked to nutrient limitation Microbes require inventive ways to acquire scarce nutrients from the environment. Enzymes that catalyze the acquisition of phosphorus from dissolved organic matter, for example, rely on complex metal cofactors in the active site. Yong et al. determined the crystal structure of the PhoX alkaline phosphatase from Pseudomonas fluorescens (see the Perspective by Moore). The metal centers arrange themselves in a triangular structure of two iron atoms and one calcium atom, bridged together by an oxide ion. The presence of iron, which itself is a trace nutrient in most environments, suggests that it limits phosphorus acquisition. Science , this issue p. 1170 ; see also p. 1120