FmdE, Molybdenum formylmethanofuran dehydrogenase operon

This entry represents the FmdE protein that is encode by the molybdenum formylmethanofuran dehydrogenase operon. FmdE does not co-purify with the molybdenum isozyme that is formed by FmdC and FmdB [1]. The domain is typically found as a single copy, but is repeated in some sequence two to three times. It is also common place to find this domain co-occurs with a zinc-beta ribbon domain, suggesting that is may bind nucleic acid and be involved in transcription regulation.

Literature references

1. Hochheimer A, Linder D, Thauer RK, Hedderich R;, Eur J Biochem. 1996;242:156-162.: The molybdenum formylmethanofuran dehydrogenase operon and the tungsten formylmethanofuran dehydrogenase operon from Methanobacterium thermoautotrophicum. Structures and transcriptional regulation. PUBMED:8954165

InterPro entry IPR003814

Formylmethanofuran dehydrogenases () is found in methanogenic and sulphate-reducing archaea. The enzyme contains molybdenum or tungsten, a molybdopterin guanine dinuceotide cofactor (MGD) and iron-sulphur clusters PUBMED:8125106. It catalyses the reversible reduction of CO₂ and methanofuran via N-carboxymethanofuran (carbamate) to N-formylmethanofuran, the first and second steps in methanogenesis from CO₂ PUBMED:8575452, PUBMED:9342247. This reaction is important for the reduction of CO₂ to methane, in autotrophic CO₂ fixation, and in CO₂ formation from reduced C₁ units PUBMED:8954165. The synthesis of formylmethanofuran is crucial for the energy metabolism of archaea. Methanogenic archaea derives the energy for autrophic growth from the reduction of CO₂ with molecular hydrogen as the electron donor PUBMED:12492476. The process of methanogenesis consists of a series of reduction reactions at which the one-carbon unit derived from CO₂ is bound to C₁ carriers.

There are two isoenzymes of formylmethanofuran dehydrogenase: a tungsten-containing isoenzyme (Fwd) and a molybdenum-containing isoenzyme (Fmd). The tungsten isoenzyme is constitutively transcribed, whereas transcription of the molybdenum operon is induced by molybdate PUBMED:9818358. The archaea Methanobacterium thermoautotrophicum contains a 4-subunit (FwdA, FwdB, FwdC, FwdD) tungsten formylmethanofuran dehydrogenase and a 3-subunit (FmdA, FmdB, FmdC) molybdenum formylmethanofuran dehydrogenase PUBMED:8954165.

This entry represents subunit E of formylmethanofuran dehydrogenase enyzmes. The enzyme from Methanosarcina barkeri is a molybdenum iron-sulphur protein involved in methanogenesis. Subunit E protein is co-expressed with the enzyme but fails to co-purify and thus its function is unknown PUBMED:8617280.

External database links

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Formatting options

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER2.

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

This page displays the phylogenetic tree for this family. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

HMM information

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the FmdE domain has been found.