Summary: Germination protease
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Germination protease Provide feedback
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External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR005080
In the MEROPS database peptidases and peptidase homologues are grouped into clans and families. Clans are groups of families for which there is evidence of common ancestry based on a common structural fold:
- Each clan is identified with two letters, the first representing the catalytic type of the families included in the clan (with the letter 'P' being used for a clan containing families of more than one of the catalytic types serine, threonine and cysteine). Some families cannot yet be assigned to clans, and when a formal assignment is required, such a family is described as belonging to clan A-, C-, M-, N-, S-, T- or U-, according to the catalytic type. Some clans are divided into subclans because there is evidence of a very ancient divergence within the clan, for example MA(E), the gluzincins, and MA(M), the metzincins.
- Peptidase families are grouped by their catalytic type, the first character representing the catalytic type: A, aspartic; C, cysteine; G, glutamic acid; M, metallo; N, asparagine; S, serine; T, threonine; and U, unknown. The serine, threonine and cysteine peptidases utilise the amino acid as a nucleophile and form an acyl intermediate - these peptidases can also readily act as transferases. In the case of aspartic, glutamic and metallopeptidases, the nucleophile is an activated water molecule. In the case of the asparagine endopeptidases, the nucleophile is asparagine and all are self-processing endopeptidases.
In many instances the structural protein fold that characterises the clan or family may have lost its catalytic activity, yet retain its function in protein recognition and binding.
Aspartic endopeptidases EC of vertebrate, fungal and retroviral origin have been characterised [PUBMED:1455179]. More recently, aspartic endopeptidases associated with the processing of bacterial type 4 prepilin [PUBMED:10625704] and archaean preflagellin have been described [PUBMED:16983194, PUBMED:14622420].
Structurally, aspartic endopeptidases are bilobal enzymes, each lobe contributing a catalytic Asp residue, with an extended active site cleft localised between the two lobes of the molecule. One lobe has probably evolved from the other through a gene duplication event in the distant past. In modern-day enzymes, although the three-dimensional structures are very similar, the amino acid sequences are more divergent, except for the catalytic site motif, which is very conserved. The presence and position of disulphide bridges are other conserved features of aspartic peptidases. All or most aspartate peptidases are endopeptidases. These enzymes have been assigned into clans (proteins which are evolutionary related), and further sub-divided into families, largely on the basis of their tertiary structure.
Metalloproteases are the most diverse of the four main types of protease, with more than 30 families identified to date [PUBMED:7674922]. In these enzymes, a divalent cation, usually zinc, activates the water molecule. The metal ion is held in place by amino acid ligands, usually three in number. The known metal ligands are His, Glu, Asp or Lys and at least one other residue is required for catalysis, which may play an electrophillic role. Of the known metalloproteases, around half contain an HEXXH motif, which has been shown in crystallographic studies to form part of the metal-binding site [PUBMED:7674922]. The HEXXH motif is relatively common, but can be more stringently defined for metalloproteases as abXHEbbHbc, where 'a' is most often valine or threonine and forms part of the S1' subsite in thermolysin and neprilysin, 'b' is an uncharged residue, and 'c' a hydrophobic residue. Proline is never found in this site, possibly because it would break the helical structure adopted by this motif in metalloproteases [PUBMED:7674922].
This group of metallopeptidases belong to MEROPS peptidase family A25 (gpr protease family, clan AE). These are tetrameric proteases that makes the rate-limiting first cut in the small, acid-soluble spore proteins (SASP) of Bacillus subtilis and related species during spore germination. The enzyme lacks clear homology to other known proteases. It processes its own amino end before becoming active to cleave SASPs.
|Molecular function||peptidase activity (GO:0008233)|
|Biological process||proteolysis (GO:0006508)|
|spore germination (GO:0009847)|
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This clan contains HybD-like domains. HybD is a nickel binding endopeptidase. Structural and sequences analyses have highlighted the presence of two highly conserved motifs that are shared with germination proteases and HybD . Members of this clan adopt an alpha/beta fold, comprised of a central beta sheet, surrounded by alpha helices.
The clan contains the following 3 members:DUF1256 HycI Peptidase_A25
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
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Curation and family details
|Previous IDs:||Peptidase_U3; Peptidase_M63;|
|Number in seed:||2|
|Number in full:||602|
|Average length of the domain:||219.30 aa|
|Average identity of full alignment:||31 %|
|Average coverage of the sequence by the domain:||94.65 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||9|
|Download:||download the raw HMM for this family|
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There is 1 interaction for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe 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 Peptidase_A25 domain has been found. There are 2 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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