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PDBsum entry 4j1y

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protein Protein-protein interface(s) links
Hydrolase PDB id
4j1y

 

 

 

 

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Contents
Protein chain
378 a.a.
Waters ×41
PDB id:
4j1y
Name: Hydrolase
Title: The x-ray crystal structure of human complement protease c1s zymogen
Structure: Complement c1s subcomponent. Chain: a, b. Fragment: ccp1-ccp2-spz (unp residues 292-698). Synonym: c1 esterase, complement component 1 subcomponent s, complement c1s subcomponent heavy chain, complement c1s subcomponent light chain. Engineered: yes. Mutation: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: c1s. Expressed in: escherichia coli. Expression_system_taxid: 562.
Resolution:
2.66Å     R-factor:   0.203     R-free:   0.259
Authors: A.J.Perry,L.C.Wijeyewickrema,P.G.Wilmann,M.J.Gunzburg,L.D'Andrea, J.A.Irving,S.S.Pang,R.C.Duncan,J.A.Wilce,J.C.Whisstock,R.N.Pike
Key ref: A.J.Perry et al. (2013). A molecular switch governs the interaction between the human complement protease C1s and its substrate, complement C4. J Biol Chem, 288, 15821-15829. PubMed id: 23592783 DOI: 10.1074/jbc.M113.464545
Date:
03-Feb-13     Release date:   24-Apr-13    
PROCHECK
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 Headers
 References

Protein chains
Pfam   ArchSchema ?
P09871  (C1S_HUMAN) -  Complement C1s subcomponent from Homo sapiens
Seq:
Struc:
 
Seq:
Struc:
688 a.a.
378 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.3.4.21.42  - complement subcomponent C1s.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Cleaves component C4 to C4a and C4b (Arg-|-Ala bond), and component C2 to C2a and C2b (Lys(or Arg)-|-Lys bond).

 

 
DOI no: 10.1074/jbc.M113.464545 J Biol Chem 288:15821-15829 (2013)
PubMed id: 23592783  
 
 
A molecular switch governs the interaction between the human complement protease C1s and its substrate, complement C4.
A.J.Perry, L.C.Wijeyewickrema, P.G.Wilmann, M.J.Gunzburg, L.D'Andrea, J.A.Irving, S.S.Pang, R.C.Duncan, J.A.Wilce, J.C.Whisstock, R.N.Pike.
 
  ABSTRACT  
 
The complement system is an ancient innate immune defense pathway that plays a front line role in eliminating microbial pathogens. Recognition of foreign targets by antibodies drives sequential activation of two serine proteases, C1r and C1s, which reside within the complement Component 1 (C1) complex. Active C1s propagates the immune response through its ability to bind and cleave the effector molecule complement Component 4 (C4). Currently, the precise structural and biochemical basis for the control of the interaction between C1s and C4 is unclear. Here, using surface plasmon resonance, we show that the transition of the C1s zymogen to the active form is essential for C1s binding to C4. To understand this, we determined the crystal structure of a zymogen C1s construct (comprising two complement control protein (CCP) domains and the serine protease (SP) domain). These data reveal that two loops (492-499 and 573-580) in the zymogen serine protease domain adopt a conformation that would be predicted to sterically abrogate C4 binding. The transition from zymogen to active C1s repositions both loops such that they would be able to interact with sulfotyrosine residues on C4. The structure also shows the junction of the CCP1 and CCP2 domains of C1s for the first time, yielding valuable information about the exosite for C4 binding located at this position. Together, these data provide a structural explanation for the control of the interaction with C1s and C4 and, furthermore, point to alternative strategies for developing therapeutic approaches for controlling activation of the complement cascade.
 

 

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