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. Author manuscript; available in PMC: 2014 Dec 20.
Published in final edited form as: Science. 2013 Oct 31;342(6165):10.1126/science.1245625. doi: 10.1126/science.1245625

Fig. 4. Complete structural definition of the PGT122 epitope.

Fig. 4

(A) In addition to the N332 glycan (yellow), the PGT122 bnAb recognizes both protein and glycan elements near the base of gp120 V1 (orange) and V3 (red) to mediate broad and potent HIV-1 neutralization. Heavy and light chain CDRs are shown as dark and light blue tubes, respectively. Electron density for oligomannose glycans (spheres) surrounding the PGT122 epitope is shown as a 2Fo-Fc gray mesh contoured at 1.0 σ. (B) Superimposition of the PGT122 epitope with glycans from PGT121 (PDB ID: 4JY4 and 4FQC, (23, 55)) and PG16 (PDB ID: 4DQO, (6)) liganded crystal structures. PGT122 binding is compatible with the involvement of complex/hybrid glycans at gp120 N137 and N156/173 (green) when the trimer is expressed in human cells capable of making this type of glycan. The figure was generated with Pymol (63). (C) The use of glycan knock-out mutants of HIV-1 BG505 pseudoviruses reveals the importance of glycans at N137, N156 and N301 for PGT122 recognition and neutralization. These glycans are part of the PGT122 epitope in the trimer crystal structure to varying extents.