Comparative Genomics and Proteomic Analysis of Assimilatory Sulfate Reduction Pathways in Anaerobic Methanotrophic Archaea

Tutkimustuotos: Lehtiartikkelivertaisarvioitu

Tutkijat

  • Hang Yu
  • Dwi Susanti
  • Shawn E. McGlynn
  • Connor T. Skennerton
  • Karuna Chourey
  • Ramsunder Iyer
  • Silvan Scheller

  • Patricia L. Tavormina
  • Robert L. Hettich
  • Biswarup Mukhopadhyay
  • Victoria J. Orphan

Organisaatiot

  • California Institute of Technology
  • Virginia Tech
  • Oak Ridge National Laboratory
  • University of Tennessee, Knoxville

Kuvaus

Sulfate is the predominant electron acceptor for anaerobic oxidationof methane (AOM) in marine sediments. This process is carried out by a syntrophic consortium of anaerobic methanotrophic archaea (ANME) and sulfate reducing bacteria (SRB) through an energy conservation mechanism that is still poorly understood. It was previously hypothesized that ANME alone could couple methane oxidation to dissimilatory sulfate reduction, but a genetic and biochemical basis for this proposal has not been identified. Using comparative genomic and phylogenetic analyses, we found the genetic capacity in ANME and related methanogenic archaea for sulfate reduction, including sulfate adenylyltransferase, APS kinase, APS/PAPS reductase and two different sulfite reductases. Based on characterized homologs and the lack of associated energy conserving complexes, the sulfate reduction pathways in ANME are likely used for assimilation but not dissimilation of sulfate. Environmental metaproteomic analysis confirmed the expression of 6 proteins in the sulfate assimilation pathway of ANME. The highest expressed proteins related to sulfate assimilation were two sulfite reductases, namely assimilatory-type low-molecular-weight sulfite reductase (alSir) and a divergent group of coenzyme F420-dependent sulfite reductase (Group II Fsr). In methane seep sediment microcosm experiments, however, sulfite and zero-valent sulfur amendments were inhibitory to ANME-2a/2c while growth in their syntrophic SRB partner was not observed. Combined with our genomic and metaproteomic results, the passage of sulfur species by ANME as metabolic intermediates for their SRB partners is unlikely. Instead, our findings point to a possible niche for ANME to assimilate inorganic sulfur compounds more oxidized than sulfide in anoxic marine environments.

Yksityiskohdat

AlkuperäiskieliEnglanti
Artikkeli2917
Sivumäärä15
JulkaisuFrontiers in Microbiology
Vuosikerta9
TilaSähköinen julkaisu (e-pub) ennen painettua julkistusta - 3 joulukuuta 2018
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

ID: 30189633