Protein Family Models

This family consists of proteins predominantly found in bacteria, including Alkaline phosphatase PhoX from Pseudomonas fluorescens (Swiss:Q3K5N8), a phosphomonoesterase with no phosphodiesterase activity. This protein adopts a six-bladed beta-propeller fold, with the active site located at the bottom of the cavity at the centre of the propeller [1]. [1]. 25190793. A complex iron-calcium cofactor catalyzing phosphotransfer chemistry. Yong SC, Roversi P, Lillington J, Rodriguez F, Krehenbrink M, Zeldin OB, Garman EF, Lea SM, Berks BC;. Science. 2014;345:1170-1173. (from Pfam)

Date:

2024-10-16

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

PhoX family protein similar to Pseudomonas fluorescens alkaline phosphatase PhoX

Date:

2024-09-19