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Title: Effects of Zinc on Particulate Methane Monooxygenase Activity and Structure

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1162586
Report Number(s):
BNL-106531-2014-JA
Journal ID: ISSN 0021--9258
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Biological Chemistry; Journal Volume: 289; Journal Issue: 31
Country of Publication:
United States
Language:
English

Citation Formats

Sirajuddin, S., Barupala, D., Helling, S., Marcus, K., Stemmler, T., and Rosenzweig, A.. Effects of Zinc on Particulate Methane Monooxygenase Activity and Structure. United States: N. p., 2014. Web. doi:10.1074/jbc.M114.581363.
Sirajuddin, S., Barupala, D., Helling, S., Marcus, K., Stemmler, T., & Rosenzweig, A.. Effects of Zinc on Particulate Methane Monooxygenase Activity and Structure. United States. doi:10.1074/jbc.M114.581363.
Sirajuddin, S., Barupala, D., Helling, S., Marcus, K., Stemmler, T., and Rosenzweig, A.. Fri . "Effects of Zinc on Particulate Methane Monooxygenase Activity and Structure". United States. doi:10.1074/jbc.M114.581363.
@article{osti_1162586,
title = {Effects of Zinc on Particulate Methane Monooxygenase Activity and Structure},
author = {Sirajuddin, S. and Barupala, D. and Helling, S. and Marcus, K. and Stemmler, T. and Rosenzweig, A.},
abstractNote = {},
doi = {10.1074/jbc.M114.581363},
journal = {Journal of Biological Chemistry},
number = 31,
volume = 289,
place = {United States},
year = {Fri Aug 01 00:00:00 EDT 2014},
month = {Fri Aug 01 00:00:00 EDT 2014}
}
  • Batch culture conditions were established for the formation of H{sub 2}-driven whole-cell soluble or particulate methane monooxygenase (sMMO or pMMO) activity in the obligate methanotroph, Methylosinus trichosporium OB3b, to expand its potential uses in groundwater bioremediation and the production of specific chemicals. Addition of either Ni and H{sub 2} to a nitrate-containing minimal salts growth medium or Ni and Mo to a nitrate-lacking growth medium (induces a nitrogenase that generates intracellular H{sub 2}) markedly enhanced both the hydrogenase and the accompanying washed-cell H{sub 2}-driven MMO activities of shake-flask cultured cells. For sMMO containing cells, H{sub 2} provided in vitro reducingmore » power for the oxidation of chlorinated solvents such as chloroform and trichloroethylene. Cell cultivations under N{sub 2}-fixing conditions in a 5-L bioreactor, however, required an initial nitrate concentration of at least 1 to 2 mM to achieve high biomass yields (5 to 7 g of dry cell wt/L) for cells producing H{sub 2}-driven sMMO or pMMO activity. Elevation of the initial medium nitrate concentration to 20 mM shortened the culture time for pMMO producing cells by 40%, yet still generated an equivalent growth yield. High nitrate also shortened the culture time for sMMO containing cells by {approximately}25%, but it lowered their biomass yield by 26%. Upon storage for 5 weeks at room temperature, washed resting-state cells retained 90% and 70% of their H{sub 2}-driven sMMO and pMMO activity, respectively. This makes their practical use quite feasible.« less
  • Particulate methane monooxygenase (pMMO) is an integral membrane metalloenzyme that oxidizes methane to methanol in methanotrophic bacteria. Previous biochemical and structural studies of pMMO have focused on preparations from Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b. A pMMO from a third organism, Methylocystis species strain M, has been isolated and characterized. Both membrane-bound and solubilized Methylocystis sp. strain M pMMO contain {approx}2 copper ions per 100 kDa protomer and exhibit copper-dependent propylene epoxidation activity. Spectroscopic data indicate that Methylocystis sp. strain M pMMO contains a mixture of Cu{sup I} and Cu{sup II}, of which the latter exhibits two distinct typemore » 2 Cu{sup II} electron paramagnetic resonance (EPR) signals. Extended X-ray absorption fine structure (EXAFS) data are best fit with a mixture of Cu-O/N and Cu-Cu ligand environments with a Cu-Cu interaction at 2.52-2.64 {angstrom}. The crystal structure of Methylocystis sp. strain M pMMO was determined to 2.68 {angstrom} resolution and is the best quality pMMO structure obtained to date. It provides a revised model for the pmoA and pmoC subunits and has led to an improved model of M. capsulatus (Bath) pMMO. In these new structures, the intramembrane zinc/copper binding site has a different coordination environment from that in previous models.« less