PDBsum entry 3uir

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protein ligands Protein-protein interface(s) links
Hydrolase/hydrolase inhibitor PDB id
Protein chains
243 a.a.
56 a.a.
SO4 ×2
Waters ×104
PDB id:
Name: Hydrolase/hydrolase inhibitor
Title: Crystal structure of the plasmin-textilinin-1 complex
Structure: Plasmin light chain b. Chain: a, b. Synonym: microplasmin. Engineered: yes. Textilinin-1. Chain: c, d. Synonym: txln-1. Engineered: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: plg. Expressed in: escherichia coli. Expression_system_taxid: 562. Pseudonaja textilis textilis. Eastern brown snake. Organism_taxid: 169397.
2.78Å     R-factor:   0.211     R-free:   0.258
Authors: L.W.Guddat,E.K.Millers,J.De Jersey,M.F.Lavin,P.M.Masci
Key ref: E.K.Millers et al. (2013). The structure of human microplasmin in complex with textilinin-1, an aprotinin-like inhibitor from the Australian brown snake. PLoS One, 8, e54104. PubMed id: 23335990 DOI: 10.1371/journal.pone.0054104
05-Nov-11     Release date:   26-Dec-12    
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Protein chains
Pfam   ArchSchema ?
P00747  (PLMN_HUMAN) -  Plasminogen
810 a.a.
243 a.a.
Protein chains
Pfam   ArchSchema ?
Q90WA1  (IVBI1_PSETT) -  Kunitz-type serine protease inhibitor textilinin-1
83 a.a.
56 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: Chains A, B: E.C.  - Plasmin.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Preferential cleavage: Lys-|-Xaa > Arg-|-Xaa; higher selectivity than trypsin. Converts fibrin into soluble products.
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   1 term 
  Biological process     proteolysis   3 terms 
  Biochemical function     catalytic activity     4 terms  


DOI no: 10.1371/journal.pone.0054104 PLoS One 8:e54104 (2013)
PubMed id: 23335990  
The structure of human microplasmin in complex with textilinin-1, an aprotinin-like inhibitor from the Australian brown snake.
E.K.Millers, L.A.Johnson, G.W.Birrell, P.P.Masci, M.F.Lavin, Jersey, L.W.Guddat.
Textilinin-1 is a Kunitz-type serine protease inhibitor from Australian brown snake venom. Its ability to potently and specifically inhibit human plasmin (K(i) = 0.44 nM) makes it a potential therapeutic drug as a systemic anti-bleeding agent. The crystal structures of the human microplasmin-textilinin-1 and the trypsin-textilinin-1 complexes have been determined to 2.78 Å and 1.64 Å resolution respectively, and show that textilinin-1 binds to trypsin in a canonical mode but to microplasmin in an atypical mode with the catalytic histidine of microplasmin rotated out of the active site. The space vacated by the histidine side-chain in this complex is partially occupied by a water molecule. In the structure of microplasminogen the χ(1) dihedral angle of the side-chain of the catalytic histidine is rotated by 67° from its "active" position in the catalytic triad, as exemplified by its location when microplasmin is bound to streptokinase. However, when textilinin-1 binds to microplasmin the χ(1) dihedral angle of this amino acid residue changes by -157° (i.e. in the opposite rotation direction compared to microplasminogen). The unusual mode of interaction between textilinin-1 and plasmin explains textilinin-1's selectivity for human plasmin over plasma kallikrein. This difference can be exploited in future drug design efforts.