Butane monooxygenase of 'Pseudomonas butanovora': purification and biochemical characterization of a terminal-alkane hydroxylating diiron monooxygenase

• Published in: Microbiology (Society for General Microbiology) 2007-06, Vol.153 (6), p.1808-1816
• Main Authors: Dubbels, Bradley L, Sayavedra-Soto, Luis A, Arp, Daniel J
• Format: Article
• Language: English
• Subjects: Alkanes - metabolism; Bacteriology; Biological and medical sciences; Butanes - metabolism; Electrophoresis, Polyacrylamide Gel; Enzyme Activators - pharmacology; Enzyme Stability - drug effects; Ethylenes - metabolism; FMN Reductase - isolation & purification; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide - metabolism; Iron - pharmacology; Metabolism. Enzymes; Methylosinus trichosporium; Methylosinus trichosporium - enzymology; Microbiology; Mixed Function Oxygenases - chemistry; Mixed Function Oxygenases - isolation & purification; Mixed Function Oxygenases - metabolism; Oxidation-Reduction; Protein Subunits; Pseudomonas - enzymology; Pseudomonas - metabolism; Pseudomonas butanovora; Spectrum Analysis; Substrate Specificity
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2006/004960-0

Department of Botany and Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, OR 97331-2902, USA Correspondence Daniel J. Arp arpd{at}science.oregonstate.edu Butane monooxygenase (sBMO) has been purified to homogeneity from the Gram-negative β -proteobacterium ‘ Pseudomonas butanovora ’ and confirmed to be a three-component diiron monooxygenase system. The reconstituted enzyme complex oxidized C 3 –C 6 linear and branched aliphatic alkanes, which are growth substrates for ‘ P. butanovora ’. The sBMO complex was composed of an iron-containing hydroxylase (BMOH), a flavo-iron sulfur-containing NADH-oxidoreductase (BMOR) and a small regulatory component protein (BMOB). The physical characteristics of sBMO were remarkably similar to the sMMO family of soluble multicomponent diiron monooxgenases. However, the catalytic properties of sBMO were quantitatively different in regard to inactivation in the presence of substrate and product distribution. BMOH was capable of ethene oxidation when supplied with H 2 O 2 and ethene (known as the peroxide shunt), but this activity was at least three orders of magnitude less than that observed for the hydroxylase of sMMO of Methylosinus trichosporium OB3b. BMOH and BMOR were efficient in the oxidation of ethene in the absence of BMOB with regard to rate of reaction and product yield. Regiospecificity of sBMO was strongly biased towards primary hydroxylation, with 80 % of the hydroxylations occurring at the terminal carbon atom. Abbreviations: BMOB, butane monooxygenase regulatory component; BMOH, butane monooxygenase hydroxylase; BMOR, butane monooxygenase reductase; MMOB, methane monooxygenase regulatory component; MMOH, methane monooxygenase hydroxylase; MMOR, methane monooxygense reductase; sBMO, soluble butane monooxygenase; sMMO, soluble methane monooxygenase; T2MO, toluene 2-monooxygenase A supplementary table summarizing the purification of sBMO components is available with the online version of this paper.