4J1Y

The X-ray crystal structure of human complement protease C1s zymogen


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6645 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.201 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

A Molecular Switch Governs the Interaction between the Human Complement Protease C1s and Its Substrate, Complement C4.

Perry, A.J.Wijeyewickrema, L.C.Wilmann, P.G.Gunzburg, M.J.D'Andrea, L.Irving, J.A.Pang, S.S.Duncan, R.C.Wilce, J.A.Whisstock, J.C.Pike, R.N.

(2013) J.Biol.Chem. 288: 15821-15829

  • DOI: 10.1074/jbc.M113.464545

  • PubMed 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 r ...

    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.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Monash University, Clayton, Melbourne, Victoria 3800, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C1s subcomponent
A, B
397Homo sapiensGene Names: C1S
EC: 3.4.21.42
Find proteins for P09871 (Homo sapiens)
Go to Gene View: C1S
Go to UniProtKB:  P09871
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6645 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.201 
  • Space Group: C 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 149.890α = 90.00
b = 158.900β = 90.00
c = 78.700γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
BALBESphasing
Aimlessdata scaling
ADSCdata collection
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-04-24
    Type: Initial release
  • Version 1.1: 2013-05-01
    Type: Database references
  • Version 1.2: 2013-06-19
    Type: Database references
  • Version 1.3: 2013-07-03
    Type: Structure summary