3MUH

Crystal structure of PG9 light chain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.277 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.248 

wwPDB Validation 3D Report Full Report



Literature

Structure and function of broadly reactive antibody PG16 reveal an H3 subdomain that mediates potent neutralization of HIV-1.

Pejchal, R.Walker, L.M.Stanfield, R.L.Phogat, S.K.Koff, W.C.Poignard, P.Burton, D.R.Wilson, I.A.

(2010) Proc Natl Acad Sci U S A 107: 11483-11488

  • DOI: 10.1073/pnas.1004600107
  • Primary Citation of Related Structures:  
    3MUG, 3MUH

  • PubMed Abstract: 
  • Development of an effective vaccine against HIV-1 will likely require elicitation of broad and potent neutralizing antibodies against the trimeric surface envelope glycoprotein (Env). Monoclonal antibodies (mAbs) PG9 and PG16 neutralize approximately ...

    Development of an effective vaccine against HIV-1 will likely require elicitation of broad and potent neutralizing antibodies against the trimeric surface envelope glycoprotein (Env). Monoclonal antibodies (mAbs) PG9 and PG16 neutralize approximately 80% of HIV-1 isolates across all clades with extraordinary potency and target novel epitopes preferentially expressed on Env trimers. As these neutralization properties are ideal for a vaccine-elicited antibody response to HIV-1, their structural basis was investigated. The crystal structure of the antigen-binding fragment (Fab) of PG16 at 2.5 A resolution revealed its unusually long, 28-residue, complementarity determining region (CDR) H3 forms a unique, stable subdomain that towers above the antibody surface. A 7-residue "specificity loop" on the "hammerhead" subdomain was identified that, when transplanted from PG16 to PG9 and vice versa, accounted for differences in the fine specificity and neutralization of these two mAbs. The PG16 electron density maps also revealed that a CDR H3 tyrosine was sulfated, which was confirmed for both PG9 (doubly) and PG16 (singly) by mass spectral analysis. We further showed that tyrosine sulfation plays a role in binding and neutralization. An N-linked glycan modification is observed in the variable light chain, but not required for antigen recognition. Further, the crystal structure of the PG9 light chain at 3.0 A facilitated homology modeling to support the presence of these unusual features in PG9. Thus, PG9 and PG16 use unique structural features to mediate potent neutralization of HIV-1 that may be of utility in antibody engineering and for high-affinity recognition of a variety of therapeutic targets.


    Organizational Affiliation

    Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Antibody PG9 light chainL216Homo sapiensMutation(s): 0 
Protein Feature View
Expand
 ( Mouse scroll to zoom / Hold left click to move )
  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
A
2 N-Glycosylation Oligosaccharides Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.277 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.248 
  • Space Group: P 62 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 87.43α = 90
b = 87.43β = 90
c = 198.46γ = 120
Software Package:
Software NamePurpose
MAR345data collection
PHASERphasing
BUSTERrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-06-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-08
    Changes: Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary