AIkB, the integral membrane diiron alkane monooxgenase from Pseudomonas putida (formerly Pseudomonas oleovorans GPol) and the related enzyme xylene monooxygenase (which hydroxylates the methyl group of xylene) (XylM) are among the least well characterized diiron hydroxylases. AIkB is found in numerous bacteria, including many pathogen c genera. Mycobacterium tuberculosis, Legionella pneumophilia, and Pseudomonas aeruginosa all have genes that code for proteins with high homology to AIkB. This AREA grant explores the hypothesis that active site structure affects the mechanisms by which diiron hydroxylases oxidize alkanes. Specifically, it tests the hypothesis that the presence of the softer nitrogen donors found in the active sites of AIkB and XylM alters the reactivity of the active intermediate of these enzymes relative to the reactivity of the active intermediate of sMMO and T4MOH, which contain oxygen rich coordination environments for their diiron centers. It also tests the hypothesis that hydrophobic substrate molecules in the active site may alter the reactivity of AIkB. These hypotheses are tested by stabilizing active purified membrane-spanning diiron non-heme enzymes, characterizing their hydroxylation mechanisms using a suite of diagnostic substrates and comparing their mechanisms to the mechanism of hydroxylation of a non-heme diiron biomimetic model, using the same suite of diagnostic substrates. The training of a post-doctoral associate and undergraduate researchers figures prominently in the projects aims.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
1R15GM072506-01
Application #
6847374
Study Section
Physical Biochemistry Study Section (PB)
Program Officer
Preusch, Peter C
Project Start
2005-03-01
Project End
2009-07-31
Budget Start
2005-03-01
Budget End
2009-07-31
Support Year
1
Fiscal Year
2005
Total Cost
$208,650
Indirect Cost
Name
Bates College
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
058951401
City
Lewiston
State
ME
Country
United States
Zip Code
04240
Hsieh, Chun H; Huang, Xiongyi; Amaya, José A et al. (2017) The Enigmatic P450 Decarboxylase OleT Is Capable of, but Evolved To Frustrate, Oxygen Rebound Chemistry. Biochemistry 56:3347-3357
Austin, Rachel Narehood; Saito, Mak A (2014) Metals in marine biochemistry. Metallomics 6:1105-6
Austin, Rachel Narehood; Kenney, Grace E; Rosenzweig, Amy C (2014) Perspective: what is known, and not known, about the connections between alkane oxidation and metal uptake in alkanotrophs in the marine environment. Metallomics 6:1121-5
Naing, Swe-Htet; Parvez, Saba; Pender-Cudlip, Marilla et al. (2013) Substrate specificity and reaction mechanism of purified alkane hydroxylase from the hydrocarbonoclastic bacterium Alcanivorax borkumensis (AbAlkB). J Inorg Biochem 121:46-52
Cooper, Harriet L R; Mishra, Girish; Huang, Xiongyi et al. (2012) Parallel and competitive pathways for substrate desaturation, hydroxylation, and radical rearrangement by the non-heme diiron hydroxylase AlkB. J Am Chem Soc 134:20365-75
Austin, Rachel N; Luddy, Kate; Erickson, Karla et al. (2008) Cage escape competes with geminate recombination during alkane hydroxylation by the diiron oxygenase AlkB. Angew Chem Int Ed Engl 47:5232-4
Chakrabarty, Sarmistha; Austin, Rachel N; Deng, Dayi et al. (2007) Radical intermediates in monooxygenase reactions of rieske dioxygenases. J Am Chem Soc 129:3514-5
Rozhkova-Novosad, Elena A; Chae, Jong-Chan; Zylstra, Gerben J et al. (2007) Profiling mechanisms of alkane hydroxylase activity in vivo using the diagnostic substrate norcarane. Chem Biol 14:165-72
Austin, Rachel N; Deng, Dayi; Jiang, Yongying et al. (2006) The diagnostic substrate bicyclohexane reveals a radical mechanism for bacterial cytochrome P450 in whole cells. Angew Chem Int Ed Engl 45:8192-4
Bertrand, Erin; Sakai, Ryo; Rozhkova-Novosad, Elena et al. (2005) Reaction mechanisms of non-heme diiron hydroxylases characterized in whole cells. J Inorg Biochem 99:1998-2006