DevS Oxy Complex Stability Identifies This Heme Protein as a Gas Sensor in Mycobacterium tuberculosis Dormancy

作者：Ioanoviciu Alexandra; Meharenna Yergalem T; Poulos Thomas L; de Montellano Paul R Ortiz^*

来源：Biochemistry, 2009, 48(25): 5839-5848.

DOI：10.1021/bi802309y

DevS is one of the two sensing kinases responsible for DevR activation and the subsequent entry of Mycobacterium tuberculosis into dormancy. Full-length wild-type DevS forms a stable oxy-ferrous complex. The DevS autoxidation rates are extremely low (half-lives of > 24 h) in the presence of cations such as K(+), Na(+), Mg(2+), and Ca(2+). At relatively high concentrations (100 MM), Cu(2+) accelerates autoxidation more than 1500-fold. Contrary to expectations, removal of the key hydrogen bond between the iron-coordinated oxygen and Tyr171 in the Y171F mutant provides a protein of comparable stability to autoxidation and similar oxygen dissociation rate. This correlates with our earlier finding that the Y171F mutant and wild-type kinase activities are similarly regulated by the binding of oxygen: namely, the ferrous five-coordinate complex is active, whereas the oxy-ferrous six-coordinate species is inactive. Our results indicate that DevS is a gas sensor in vivo rather than a redo x sensor and that the stability of its ferrous-oxy complex is enhanced by interdomain interactions.

• 出版日期2009-6-30