SUPERFAMILY 1.75 HMM library and genome assignments server

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Proteinase A inhibitor IA3 superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   All alpha proteins [ 46456] (284)
Fold:   Non-globular all-alpha subunits of globular proteins [ 48661] (14)
Superfamily:   Proteinase A inhibitor IA3 [ 48686]
Families:   Proteinase A inhibitor IA3 [ 48687]

Superfamily statistics
Genomes (28) Uniprot 2018_03 genome PDB chains (SCOP 1.75)
Domains 28 12 3
Proteins 28 12 3

Functional annotation
General category Processes_IC
Detailed category Proteases

Function annotation of SCOP domain superfamilies

InterPro annotation
Cross references IPR008956 SSF48686 Protein matches

The IA3 polypeptide of Saccharomyces cerevisiae is an 8-kDa inhibitor of the vacuolar aspartic proteinase (proteinase A or saccharopepsin, MEROPS peptidase family A1). It belongs to MEROPS inhibitor family I34, clan JA. No other aspartic proteinase has been found to be inhibited by IA3, and at least 15 aspartic proteinases related to YprA cleave IA3 as a substrate. Ligand- free IA3 has little intrinsic secondary structure, however, upon contact with proteinase A, residues 2-32 of the inhibitor become ordered and adopt a near perfect alpha-helical conformation occupying the active site cleft of the enzyme. This potent, specific interaction is directed primarily by hydrophobic interactions made by three key features in the inhibitory sequence [PubMed11042188].

InterPro database

PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation ]

Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.

Alignments of sequences to 1 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.

Browse and view proteins in genomes which have different domain combinations including a Proteinase A inhibitor IA3 domain.

Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.

Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 1 hidden Markov models representing the Proteinase A inhibitor IA3 superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.

Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Internal database links ]