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This article is part of the Research Topic Microbial enzymes that oxidize hydrocarbons

Original Research ARTICLE

Front. Microbiol., 10 May 2013 | http://dx.doi.org/10.3389/fmicb.2013.00109

Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents

Erin M. Bertrand1,2, Ramaydalis Keddis3,4, John T. Groves5, Costantino Vetriani3,4 and Rachel Narehood Austin1*
  • 1Department of Chemistry, Bates College, Lewiston, ME, USA
  • 2Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, CA, USA
  • 3Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
  • 4Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
  • 5Department of Chemistry, Princeton University, Princeton, NJ, USA

Six aerobic alkanotrophs (organism that can metabolize alkanes as their sole carbon source) isolated from deep-sea hydrothermal vents were characterized using the radical clock substrate norcarane to determine the metalloenzyme and reaction mechanism used to oxidize alkanes. The organisms studied were Alcanivorax sp. strains EPR7 and MAR14, Marinobacter sp. strain EPR21, Nocardioides sp. strains EPR26w, EPR28w, and Parvibaculum hydrocarbonoclasticum strain EPR92. Each organism was able to grow on n-alkanes as the sole carbon source and therefore must express genes encoding an alkane-oxidizing enzyme. Results from the oxidation of the radical-clock diagnostic substrate norcarane demonstrated that five of the six organisms (EPR7, MAR14, EPR21, EPR26w, and EPR28w) used an alkane hydroxylase functionally similar to AlkB to catalyze the oxidation of medium-chain alkanes, while the sixth organism (EPR92) used an alkane-oxidizing cytochrome P450 (CYP)-like protein to catalyze the oxidation. DNA sequencing indicated that EPR7 and EPR21 possess genes encoding AlkB proteins, while sequencing results from EPR92 confirmed the presence of a gene encoding CYP-like alkane hydroxylase, consistent with the results from the norcarane experiments.

Keywords: alkanotrophs, hydrocarbon oxidation, deep-sea hydrothermal vents, alkanes, alkane hydroxylases

Citation: Bertrand EM, Keddis R, Groves JT, Vetriani C and Austin RN (2013) Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents. Front. Microbiol. 4:109. doi: 10.3389/fmicb.2013.00109

Received: 07 January 2013; Paper pending published: 10 February 2013;
Accepted: 16 April 2013; Published online: 10 May 2013.

Edited by:

Amy V. Callaghan, University of Oklahoma, USA

Reviewed by:

Eric Boyd, Montana State University, USA
John W. Moreau, University of Melbourne, Australia

Copyright © 2013 Bertrand, Keddis, Groves, Vetriani and Austin. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.

*Correspondence: Rachel Narehood Austin, Department of Chemistry, Bates College, 5 Andrews Rd., Lewiston, 04240 ME, USA. e-mail: raustin@bates.edu