4MHE

Crystal structure of CC-chemokine 18


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.180 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structures of human CCL18, CCL3, and CCL4 reveal molecular determinants for quaternary structures and sensitivity to insulin-degrading enzyme.

Liang, W.G.Ren, M.Zhao, F.Tang, W.J.

(2015) J Mol Biol 427: 1345-1358

  • DOI: https://doi.org/10.1016/j.jmb.2015.01.012
  • Primary Citation of Related Structures:  
    3TN2, 4MHE, 4RA8, 4RAL

  • PubMed Abstract: 

    CC chemokine ligands (CCLs) are 8- to 14-kDa signaling proteins involved in diverse immune functions. While CCLs share similar tertiary structures, oligomerization produces highly diverse quaternary structures that protect chemokines from proteolytic degradation and modulate their functions. CCL18 is closely related to CCL3 and CCL4 with respect to both protein sequence and genomic location, yet CCL18 has distinct biochemical and biophysical properties. Here, we report a crystal structure of human CCL18 and its oligomerization states in solution based on crystallographic and small-angle X-ray scattering analyses. Our data show that CCL18 adopts an α-helical conformation at its N-terminus that weakens its dimerization, explaining CCL18's preference for the monomeric state. Multiple contacts between monomers allow CCL18 to reversibly form a unique open-ended oligomer different from those of CCL3, CCL4, and CCL5. Furthermore, these differences hinge on proline 8, which is conserved in CCL3 and CCL4 but is replaced by lysine in human CCL18. Our structural analyses suggest that a mutation of proline 8 to alanine stabilizes a type 1 β-turn at the N-terminus of CCL4 to prevent dimerization but prevents dimers from making key contacts with each other in CCL3. Thus, the P8A mutation induces depolymerization of CCL3 and CCL4 by distinct mechanisms. Finally, we used structural, biochemical, and functional analyses to unravel why insulin-degrading enzyme degrades CCL3 and CCL4 but not CCL18. Our results elucidate the molecular basis for the oligomerization of three closely related CC chemokines and suggest how oligomerization shapes CCL chemokine function.


  • Organizational Affiliation

    Ben May Department for Cancer Research, The University of Chicago, IL 60637, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
C-C motif chemokine 18
A, B, C, D
70Homo sapiensMutation(s): 0 
Gene Names: CCL18AMAC1DCCK1MIP4PARCSCYA18
UniProt & NIH Common Fund Data Resources
Find proteins for P55774 (Homo sapiens)
Explore P55774 
Go to UniProtKB:  P55774
PHAROS:  P55774
GTEx:  ENSG00000275385 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP55774
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download Ideal Coordinates CCD File 
E [auth B]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.180 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.075α = 90
b = 55.168β = 109.25
c = 60.377γ = 90
Software Package:
Software NamePurpose
HKL-3000data collection
PHASERphasing
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-09-03
    Type: Initial release
  • Version 1.1: 2015-05-13
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description