4JY4

Crystal structure of human Fab PGT121, a broadly reactive and potent HIV-1 neutralizing antibody


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Broadly neutralizing antibody PGT121 allosterically modulates CD4 binding via recognition of the HIV-1 gp120 V3 base and multiple surrounding glycans.

Julien, J.P.Sok, D.Khayat, R.Lee, J.H.Doores, K.J.Walker, L.M.Ramos, A.Diwanji, D.C.Pejchal, R.Cupo, A.Katpally, U.Depetris, R.S.Stanfield, R.L.McBride, R.Marozsan, A.J.Paulson, J.C.Sanders, R.W.Moore, J.P.Burton, D.R.Poignard, P.Ward, A.B.Wilson, I.A.

(2013) PLoS Pathog 9: e1003342-e1003342

  • DOI: https://doi.org/10.1371/journal.ppat.1003342
  • Primary Citation of Related Structures:  
    4JY4, 4JY5, 4JY6

  • PubMed Abstract: 

    New broad and potent neutralizing HIV-1 antibodies have recently been described that are largely dependent on the gp120 N332 glycan for Env recognition. Members of the PGT121 family of antibodies, isolated from an African donor, neutralize ∼70% of circulating isolates with a median IC50 less than 0.05 µg ml(-1). Here, we show that three family members, PGT121, PGT122 and PGT123, have very similar crystal structures. A long 24-residue HCDR3 divides the antibody binding site into two functional surfaces, consisting of an open face, formed by the heavy chain CDRs, and an elongated face, formed by LCDR1, LCDR3 and the tip of the HCDR3. Alanine scanning mutagenesis of the antibody paratope reveals a crucial role in neutralization for residues on the elongated face, whereas the open face, which accommodates a complex biantennary glycan in the PGT121 structure, appears to play a more secondary role. Negative-stain EM reconstructions of an engineered recombinant Env gp140 trimer (SOSIP.664) reveal that PGT122 interacts with the gp120 outer domain at a more vertical angle with respect to the top surface of the spike than the previously characterized antibody PGT128, which is also dependent on the N332 glycan. We then used ITC and FACS to demonstrate that the PGT121 antibodies inhibit CD4 binding to gp120 despite the epitope being distal from the CD4 binding site. Together, these structural, functional and biophysical results suggest that the PGT121 antibodies may interfere with Env receptor engagement by an allosteric mechanism in which key structural elements, such as the V3 base, the N332 oligomannose glycan and surrounding glycans, including a putative V1/V2 complex biantennary glycan, are conformationally constrained.


  • Organizational Affiliation

    Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PGT121 heavy chainA [auth B]235Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Glycosylation
Glycosylation Sites: 1
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
PGT121 light chainB [auth A]211Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

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Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
N-acetyl-alpha-neuraminic acid-(2-6)-beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose
C
9N-Glycosylation
Glycosylation Resources
GlyTouCan:  G84852GW
GlyCosmos:  G84852GW
GlyGen:  G84852GW
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.192 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.97α = 90
b = 65.72β = 90
c = 159.21γ = 90
Software Package:
Software NamePurpose
Blu-Icedata collection
PHASERphasing
PHENIXrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-05-15
    Type: Initial release
  • Version 1.1: 2014-02-05
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-09-20
    Changes: Data collection, Database references, Refinement description, Structure summary