%0 Journal Article %T The Heme-Based Oxygen-Sensor Phosphodiesterase Ec DOS (DosP): Structure-Function Relationships %A Toru Shimizu %J Biosensors %D 2013 %I MDPI AG %R 10.3390/bios3020211 %X Escherichia coli Direct Oxygen Sensor ( Ec DOS, also known as Ec DosP) is a heme-based O 2-sensing phosphodiesterase from Escherichia coli that catalyzes the conversion of cyclic-di-GMP to linear di-GMP. Cyclic-di-GMP is an important second messenger in bacteria, highlighting the importance of understanding structure-function relationships of Ec DOS. Ec DOS is composed of an N-terminal heme-bound O 2-sensing PAS domain and a C-terminal phosphodiesterase catalytic domain. Notably, its activity is markedly enhanced by O 2 binding to the heme Fe(II) complex in the PAS sensor domain. X-ray crystal structures and spectroscopic and catalytic characterization of the wild-type and mutant proteins have provided important structural and functional clues to understanding the molecular mechanism of intramolecular catalytic regulation by O 2 binding. This review summarizes the intriguing findings that have obtained for Ec DOS. %K heme protein %K oxygen sensor %K phosphodiesterase %K c-AMP %K c-di-GMP %K signal transduction %U http://www.mdpi.com/2079-6374/3/2/211