3e8l Summary


The Crystal Structure of the Double-headed Arrowhead Protease Inhibitor A in Complex with Two Trypsins

The structure was published by Bao, R., Zhou, C.Z., Jiang, C.-H., Lin, S.X., Chi, C.W., and Chen, Y.X., in 2009 in a paper entitled "The ternary structure of double-headed arrowhead protease inhibitor API-A complexed with two trypsins reveals a novel reactive site conformation." (abstract).

This crystal structure was determined using X-ray diffraction at a resolution of 2.48 Å and deposited in 2008.

The experimental data on which the structure is based was also deposited.

This PDB entry contains a complex of 2 biomacromolecules, namely Serine proteinase inhibitor A and Cationic trypsin.

It also contains one or more heterogenic compounds (e.g., ligands, co-factors, ions, modified amino acids, etc.); see here for a complete list.

The molecule most likely forms heterotrimers.

The following tables show cross-reference information to other databases (to obtain a list of all PDB entries sharing the same property or classification, click on the magnifying glass icon):

Chain Name UniProt Name of source organism % of UniProt sequence present in the sample Residues in the sample molecules % of residues observed
C Serine proteinase inhibitor A Q7M1P4 (26-201) (Q7M1P4_SAGSA)search Sagittaria sagittifoliasearch < 90% 185 95%
A Cationic trypsin P00760 (24-246) (TRY1_BOVIN)search Bos taurussearch 94% 223 100%
B Cationic trypsin P00760 (24-246) (TRY1_BOVIN)search Bos taurussearch 94% 223 100%

This entry contains 2 unique UniProt proteins:

UniProt accession Name Organism PDB
Q7M1P4 (26 - 201) Serine proteinase inhibitor A Sagittaria sagittifolia
P00760 (24 - 246) Cationic trypsin Bos taurus

Chain Structural classification (CATH) Sequence family (Pfam)
C Trypsin and protease inhibitorsearch
A, B (P00760) Trypsin-like serine proteasessearch PF00089: Trypsinsearch

Chain ID Molecular function (GO) Biological process (GO) Cellular component (GO)
C (Q7M1P4) endopeptidase inhibitor activitysearch
A, B (P00760) protein bindingsearch serine-type endopeptidase activitysearch catalytic activitysearch hydrolase activitysearch peptidase activitysearch metal ion bindingsearch serine-type peptidase activitysearch proteolysissearch digestionsearch extracellular spacesearch extracellular regionsearch

Chain InterPro annotation
C Proteinase inhibitor I3, Kunitz legumesearch Kunitz inhibitor ST1-likesearch
A, B Peptidase S1search Peptidase S1A, chymotrypsin-typesearch Trypsin-like cysteine/serine peptidase domainsearch Peptidase S1, trypsin family, active sitesearch