Protein Family Models

Date:

2023-12-12

This domain is found in formate dehydrogenase H for which the structure is known. This first domain (residues 1 to 60) of PDB:1aa6 is an Fe4S4 cluster just below the protein surface [1]. [1]. 9036855. Crystal structure of formate dehydrogenase H: catalysis. involving Mo, molybdopterin, selenocysteine, and an Fe4S4. cluster.. Boyington JC, Gladyshev VN, Khangulov SV, Stadtman TC, Sun PD;. Science. 1997;275:1305-1308. (from Pfam)

Date:

2024-04-03

Date:

2023-12-12

Members of this family include known and probable dimethyl sulfoxide reductase (DMSO reductase) A chains. In E. coli, dmsA encodes the canonical anaerobic DMSO reductase A chain. The putative selenate reductase system paralog ynfE, as part of ynfFGH expressed from a multicopy plasmid, could complement a dmsABC deletion, suggesting a similar function and some overlap in specificity, although YnfE could not substitute for DmsA in a mixed complex.

Date:

2023-07-21

Many proteins that fold in the cytosol because a required cofactor is available there only, or because cytosolic chaperones assist in folding, or because high salt in the extracellular milieu would interfere with folding there, cannot rely on the standard general secretory (Sec) pathway for secretion across the plasma membrane. This model describes a family of predicted long, non-Sec signal sequences and signal-anchor sequences (uncleaved signal sequences). All contain a typically invariant pair of arginine residues, in a motif approximated by (S/T)-R-R-X-F-L-K, followed by a membrane-spanning hydrophobic region. The system that secretes pre-folded proteins with this motif is known as twin-arginine translocation, or TAT. Note that some variant forms, often lineage-specific ones such as the RKxFL version found in Leptospira, do occur but typically fall outside the scope of this HMM. Twin-arginine signal domains with small amino acid side chains at the -1 and -3 positions from the C-terminus of the model should be predicted to be cleaved as are Sec pathway signal sequences. The system, although far from universal in prokaryotes, is widespread in bacteria and present also in many archaea.

Date:

2019-11-27