4F57

Fab structure of a neutralizing antibody L1 from an early subtype A HIV-1 infected patient


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.186 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Viral Escape from Neutralizing Antibodies in Early Subtype A HIV-1 Infection Drives an Increase in Autologous Neutralization Breadth.

Murphy, M.K.Yue, L.Pan, R.Boliar, S.Sethi, A.Tian, J.Pfafferot, K.Karita, E.Allen, S.A.Cormier, E.Goepfert, P.A.Borrow, P.Robinson, J.E.Gnanakaran, S.Hunter, E.Kong, X.P.Derdeyn, C.A.

(2013) Plos Pathog. 9: e1003173-e1003173

  • DOI: 10.1371/journal.ppat.1003173
  • Primary Citation of Related Structures:  4F58

  • PubMed Abstract: 
  • Antibodies that neutralize (nAbs) genetically diverse HIV-1 strains have been recovered from a subset of HIV-1 infected subjects during chronic infection. Exact mechanisms that expand the otherwise narrow neutralization capacity observed during early ...

    Antibodies that neutralize (nAbs) genetically diverse HIV-1 strains have been recovered from a subset of HIV-1 infected subjects during chronic infection. Exact mechanisms that expand the otherwise narrow neutralization capacity observed during early infection are, however, currently undefined. Here we characterized the earliest nAb responses in a subtype A HIV-1 infected Rwandan seroconverter who later developed moderate cross-clade nAb breadth, using (i) envelope (Env) glycoproteins from the transmitted/founder virus and twenty longitudinal nAb escape variants, (ii) longitudinal autologous plasma, and (iii) autologous monoclonal antibodies (mAbs). Initially, nAbs targeted a single region of gp120, which flanked the V3 domain and involved the alpha2 helix. A single amino acid change at one of three positions in this region conferred early escape. One immunoglobulin heavy chain and two light chains recovered from autologous B cells comprised two mAbs, 19.3H-L1 and 19.3H-L3, which neutralized the founder Env along with one or three of the early escape variants carrying these mutations, respectively. Neither mAb neutralized later nAb escape or heterologous Envs. Crystal structures of the antigen-binding fragments (Fabs) revealed flat epitope contact surfaces, where minimal light chain mutation in 19.3H-L3 allowed for additional antigenic interactions. Resistance to mAb neutralization arose in later Envs through alteration of two glycans spatially adjacent to the initial escape signatures. The cross-neutralizing nAbs that ultimately developed failed to target any of the defined V3-proximal changes generated during the first year of infection in this subject. Our data demonstrate that this subject's first recognized nAb epitope elicited strain-specific mAbs, which incrementally acquired autologous breadth, and directed later B cell responses to target distinct portions of Env. This immune re-focusing could have triggered the evolution of cross-clade antibodies and suggests that exposure to a specific sequence of immune escape variants might promote broad humoral responses during HIV-1 infection.


    Organizational Affiliation

    Immunology and Molecular Pathogenesis Graduate Program, Emory University, Atlanta, Georgia, United States of America.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Light chain of Fab of a neutralizing antibody L1
L
213N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Heavy chain of Fab of a neutralizing antibody L1
H
226N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
H
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.186 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 152.101α = 90.00
b = 57.463β = 112.78
c = 60.038γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
MOLREPphasing
HKL-2000data reduction
Blu-Icedata collection
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2012-05-12 
  • Released Date: 2013-03-27 
  • Deposition Author(s): Pan, R.M., Kong, X.P.

Revision History 

  • Version 1.0: 2013-03-27
    Type: Initial release