In anoxic sediments of the meromictic freshwater Lake Cadagno ‘Ca. Methanoperedens’ and sulphate-reducing Desulfobacterota QYQD01 co-occur. Metagenomics revealed that ‘Ca. Methanoperedens’ genomes ha...

‘Candidatus Methanoperedens’ is a genus of strictly anaerobic methanotrophic archaea (ANME). ANME mitigate the release of methane to the atmosphere by oxidizing this potent greenhouse gas to the less potent carbon dioxide. ‘Ca. Methanoperedens’, also…

Ferritin-like proteins from the anaerobic methane-oxidizing archaeon ‘Candidatus Methanoperedens carboxydivorans’ assemble as a 12-subunit complex incorporating six heme cofactors, expanding our view ...

Metagenomic analysis of wetland soil reveals diverse interacting extrachromosomal genetic elements (ECEs) associated with the methane-oxidizing archaeon Methanoperedens. Some of these ECEs share featu...

‘Candidatus Methanoperedens’ is a genus of strictly anaerobic methanotrophic archaea (ANME). ANME mitigate the release of methane to the atmosphere by oxidizing this potent greenhouse gas to the less ...

Nitrite- and nitrate-coupled anaerobic oxidation of methane (AOM), mediated by Candidatus Methylomirabilis-like bacteria and Methanoperedens-like archaea, respectively, are two recent additions of fre...

Archaeal extrachromosomal elements (ECEs) are arguably the least well understood of all genetic elements, and few have > 200 kbp ("jumbo") genomes. Here, we report circular, jumbo ECEs with genomes of up to 535 kbp in length that associate with anaerobic methane-oxidizing Methanoperedens archaea. Notably, a 409-kbp genome related to jumbo ECEs is integrated into a subset of the ~4.2 Mbp Methanoperedens chromosomes at the tRNA-Asp genes. This represents the largest integrative element in Archaea and supports the jumbo ECE - host association. Multiple genome alignment and phylogenetic analyses suggest that the large sizes were developed by extensive DNA acquisition from Methanoperedens. The newly identified ECEs encode, and in some cases express, metabolic genes such as tetrahydromethanopterin S-methyltransferase exclusively involved in methane oxidation, and genes for nitrogen and sulfur compound transformations. Also encoded are defense systems, some of which are absent in hosts, such as hybrid Type I/Type III-A CRISPR-Cas systems. In contrast to viruses and plasmids, they have host-like replication machinery and occur at stable copy ratios of 1.44 ± 0.24 : 1 to the host. Overall, our results reveal a spectrum of jumbo ECEs of Methanoperedens, ranging from plasmid-like to minichromosome-like. ### Competing Interest Statement J.F.B. is a co-founder of Metagenomi. The remaining authors declare no competing interests. Emerson Collective (United States)

Anaerobic oxidation of methane coupled to iron reduction (Fe-AOM) is a crucial process for methane removal in terrestrial environments. However, the occurrence of Fe-AOM in natural environments is rar...

In anoxic sediments of the meromictic freshwater Lake Cadagno ‘Ca. Methanoperedens’ and sulphate-reducing Desulfobacterota QYQD01 co-occur. Metagenomics revealed that ‘Ca. Methanoperedens’ genomes ha....

Ferritin-like proteins from the anaerobic methane-oxidizing archaeon ‘Candidatus Methanoperedens carboxydivorans’ assemble as a 12-subunit complex incorporating six heme cofactors, expanding our view ...

Denitrifying anaerobic methane oxidation (DAMO) is a unique microbial process in which methane (CH4) serves as an electron donor for nitrate (NO3-) or…