Structure and Function Relationships of a Redox-Sensor Protein, Heme-Regulated Phosphodiesterase

Abstract

Heme-regulated phosphodiesterase from Escherichia coli (Ec DOS) is a novel PAS heme-sensor enzyme. Ec DOS is active in the Fe²⁺ heme-bound form, whereas it is inactive in the Fe³⁺ heme-bound form. To elucidate the mechanism of the redox-dependent heme-regulated catalysis, we examined spectroscopic and functional characters of site-directed and deletion mutant proteins. We also determined crystal structures of the wild type enzyme under various conditions. In this review, we summarized findings about heme-sensor proteins, PAS domain and phosphodiesterase in general and structure and function relationships of Ec DOS specifically.