Ohr (Organic Hydroperoxide Resistance Protein) Possesses a Previously Undescribed Activity, Lipoyl-dependent Peroxidase

Author(s)

Cussiol, Jose R. R. ^[1] ; Alegria, Thiago G. P. ^[1] ; Szweda, Luke I. ^[2] ; Netto, Luis E. S. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolut, BR-05508900 Sao Paulo - Brazil

^[2] Oklahoma Med Res Fdn, Free Rad Biol & Aging Res Program, Oklahoma City, OK 73104 - USA

• Document type: Journal article
• Source: Journal of Biological Chemistry; v. 285, n. 29, p. 21943-21950, JUL 16 2010.
• Web of Science Citations: 35

Abstract

The Ohr (organic hydroperoxide resistance) family of 15-kDa Cys-based, thiol-dependent peroxidases is central to the bacterial response to stress induced by organic hydroperoxides but not by hydrogen peroxide. Ohr has a unique three-dimensional structure and requires dithiols, but not monothiols, to support its activity. However, the physiological reducing system of Ohr has not yet been identified. Here we show that lipoylated enzymes present in the bacterial extracts of Xylella fastidiosa interacted physically and functionally with this Cys-based peroxidase, whereas thioredoxin and glutathione systems failed to support Ohr peroxidase activity. Furthermore, we could reconstitute in vitro three lipoyl-dependent systems as the Ohr physiological reducing systems. We also showed that OsmC from Escherichia coli, an orthologue of Ohr from Xylella fastidiosa, is specifically reduced by lipoyl-dependent systems. These results represent the first description of a Cys-based peroxidase that is directly reduced by lipoylated enzymes. (AU)

• FAPESP's process: 07/58147-6 - Biological aspects of thiols: protein structure, antioxidant defense, cell signaling and redox states
• Grantee: Luis Eduardo Soares Netto
• Support Opportunities: Research Projects - Thematic Grants