Title: Membrane Complexes of Syntrophomonas wolfei Involved in Syntrophic Butyrate Degradation and Hydrogen Formation

Abstract

Syntrophic butyrate metabolism involves the thermodynamically unfavorable production of hydrogen and/or formate from the high potential electron donor, butyryl-CoA. Such redox reactions can occur only with energy input by a process called reverse electron transfer. Previous studies have demonstrated that hydrogen production from butyrate requires the presence of a proton gradient, but the biochemical machinery involved has not been clearly elucidated. In this study, the gene and enzyme systems involved in reverse electron transfer by Syntrophomonas wolfei were investigated using proteomic and gene expression approaches. S. wolfei was grown in coculture with Methanospirillum hungatei or Dehalococcoides mccartyi under conditions requiring reverse electron transfer and compared to both axenic S. wolfei cultures and cocultures grown in conditions that do not require reverse electron transfer. Blue native gel analysis of membranes solubilized from syntrophically grown cells revealed the presence of a membrane-bound hydrogenase, Hyd2, which exhibited hydrogenase activity during in gel assays. Bands containing a putative iron-sulfur (FeS) oxidoreductase were detected in membranes of crotonate-grown and butyrate grown S. wolfei cells. The genes for the corresponding hydrogenase subunits, hyd2ABC, were differentially expressed at higher levels during syntrophic butyrate growth when compared to growth on crotonate. The expression of the FeS oxidoreductase genemore » increased when S. wolfei was grown with M. hungatei. Additional membrane-associated proteins detected included FoF1 ATP synthase subunits and several membrane transporters that may aid syntrophic growth. Furthermore, syntrophic butyrate metabolism can proceed exclusively by interspecies hydrogen transfer, as demonstrated by growth with D. mccartyi, which is unable to use formate. These results argue for the importance of Hyd2 and FeS oxidoreductase in reverse electron transfer during syntrophic butyrate degradation.« less

Authors:

Crable, Bryan R. ^[1]; Sieber, Jessica R. ^[1]; Mao, Xinwei ^[2]; Alvarez-Cohen, Lisa ^[2]; Gunsalus, Robert ^[3]; Ogorzalek Loo, Rachel R. ^[4]; Nguyen, Hong ^[4]; McInerney, Michael J. ^[1]

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+ Show Author Affiliations

1. Univ. of Oklahoma, Norman, OK (United States). Dept. of Microbiology and Plant Biology
2. Univ. of California, Berkeley, CA (United States). Dept. of Civil and Environmental Engineering
3. Univ. of California, Los Angeles, CA (United States). Dept. of Microbiology, Immunology, and Molecular Genetics
4. Univ. of California, Los Angeles, CA (United States). Dept. of Biological Chemistry

Publication Date:

Wed Nov 09 00:00:00 EST 2016

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of Oklahoma, Norman, OK (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; USDOE Office of Science (SC), Biological and Environmental Research (BER); National Inst. of Health (NIH) (United States); National Science Foundation (NSF)

OSTI Identifier:

1480747

Alternate Identifier(s):

OSTI ID: 1604789

Grant/Contract Number:  

AC02-05CH11231; FG02-96ER20214; FC02-02ER63421; FG03-86ER13498; R01GM085402; P42-ES04705-14; CBET-1336709

Resource Type:

Accepted Manuscript

Journal Name:

Frontiers in Microbiology

Additional Journal Information:

Journal Volume: 7; Journal ID: ISSN 1664-302X

Publisher:

Frontiers Research Foundation

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; syntrophy; methanogenesis; biohydrogen; hydrogenase; fatty acids; syntrophy, methanogenesis, biohydrogen, hydrogenase, fatty acids