PDBe 1nb3

X-ray diffraction
2.8Å resolution

Crystal structure of stefin A in complex with cathepsin H: N-terminal residues of inhibitors can adapt to the active sites of endo-and exopeptidases


Function and Biology Details

Reaction catalysed:
Hydrolysis of proteins, acting as an aminopeptidase (notably, cleaving Arg-|-Xaa bonds) as well as an endopeptidase. 
Biochemical function:
Biological process:
Cellular component:

Structure analysis Details

Assembly composition:
hetero trimer (preferred)
Entry contents:
3 distinct polypeptide molecules
Macromolecules (3 distinct):
Cystatin-A Chains: I, J, K, L
Molecule details ›
Chains: I, J, K, L
Length: 98 amino acids
Theoretical weight: 11.02 KDa
Source organism: Homo sapiens
Expression system: Escherichia coli
  • Canonical: P01040 (Residues: 1-98; Coverage: 100%)
Gene names: CSTA, STF1, STFA
Sequence domains: Cystatin domain
Structure domains: Nuclear Transport Factor 2; Chain: A,
Cathepsin H Chains: A, B, C, D
Molecule details ›
Chains: A, B, C, D
Length: 220 amino acids
Theoretical weight: 24.33 KDa
Source organism: Sus scrofa
  • Canonical: O46427 (Residues: 116-335; Coverage: 70%)
Gene name: CTSH
Sequence domains: Papain family cysteine protease
Structure domains: Cysteine proteinases
Cathepsin H mini chain Chains: P, R, S, T
Molecule details ›
Chains: P, R, S, T
Length: 8 amino acids
Theoretical weight: 849 Da
Source organism: Sus scrofa
  • Canonical: O46427 (Residues: 98-105; Coverage: 3%)
Gene name: CTSH

Ligands and Environments

2 bound ligands:

No modified residues

Experiments and Validation Details

Entry percentile scores
X-ray source: RIGAKU RU200HB
Spacegroup: P21
Unit cell:
a: 48.584Å b: 91.63Å c: 161.235Å
α: 90° β: 93.69° γ: 90°
R R work R free
0.228 0.226 0.246
Expression system: Escherichia coli