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Insights into the genomes of archaea mediating the anaerobic oxidation of methane
Author(s) -
Meyerdierks Anke,
Kube Michael,
Lombardot Thierry,
Knittel Katrin,
Bauer Margarete,
Glöckner Frank Oliver,
Reinhardt Richard,
Amann Rudolf
Publication year - 2005
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2005.00844.x
Subject(s) - archaea , biology , fosmid , anaerobic oxidation of methane , contig , genome , gene , 16s ribosomal rna , operon , genetics , ecology , methane , escherichia coli
Summary The anaerobic oxidation of methane is a globally significant process which is mediated by consortia of yet uncultivated methanotrophic archaea (ANME) and sulfate‐reducing bacteria. In order to gain deeper insights into genome characteristics of the different ANME groups, large‐insert genomic libraries were constructed using DNA extracted from a methanotrophic microbial mat growing in the anoxic part of the Black Sea, and from sediments above gas hydrates at the Hydrate Ridge off the coast of Oregon. Analysis of these fosmid libraries with respect to archaeal 16S rRNA gene diversity revealed a single ANME‐1b ribotype for the Black Sea libraries, whereas the sequences derived from the Hydrate Ridge library phylogenetically affiliated with the ANME‐2a, ANME‐2c and ANME‐3 group. Genome walking for ANME‐1b resulted in a contiguous 155 kb composite genome fragment. The comparison of a set of four genomic fragments belonging to the different ANME groups revealed differences in the rRNA operon structure and the average G+C content, with the ANME‐2c contig showing the highest divergence within the set. A detailed analysis of the ANME contigs with respect to genes putatively involved in the anaerobic oxidation of methane led to the identification of: (i) a putative N 5 ,N 10 ‐methenyltetrahydromethanopterin cyclohydrolase gene, (ii) a gene cluster supposedly encoding a novel type of heterodisulfide reductase/dehydrogenase complex and (iii) a gene cluster putatively encoding a new type of CO dehydrogenase/acetyl‐CoA synthase enzyme complex.