Saunderset al.,Science 366 , eaay7199 (2019) 6 December 2019 3of17
Fig. 1. Structural characterization and development of an HIV-1 Env antigen
capable of binding to the DH270 unmutated common ancestor (UCA).
(A) Antibody neutralization of TZM-bl cell infection was compared for HIV-1
pseudoviruses encoding CH848 10.17 gp160 Env or the same Env with
glycosylation sites at Asn^133 and Asn^138 (N133 and N138) removed by mutating
them to Asp^133 and Thr^138 (10.17DT). Neutralization titers are shown as IC 50
values. (B) The binding affinities of DH270 UCA and the first intermediate
antibody in the DH270 lineage (IA4) for CH848 10.17DT–stabilized Env trimers
was determined by surface plasmon resonance. The somatic mutations acquired
in the heavy chain variable region (VH) and light chain variable region (VL)of
DH270 IA4 are shown above and below the arrow, respectively. Improbable and
probable somatic mutations were modeled on the DH270 UCA Fab crystal structure
(PDB ID 5U0R) as red and green residues, respectively. (C) CH848 10.17DT
calcium flux induction in DH270 UCA (green), DH270.1 (orange), and negative control
(black) IgG-expressing Ramos B cells. (D) Cryo-EM reconstruction (4.2 Å resolution)
of DH270 UCA (green) bound to CH848 10.17DT–stabilized Env trimers (gray),
segmented by components. (E) Zoomed-in view of the interactive region between
DH270 UCA and CH848 10.17DT. HIV-1 Env gp120 is shown in gray, with the V3 loop in
orange and the V1 loop in red. Glycans areshowninstickrepresentationand
colored by elements, with oxygen atoms in red and nitrogen atoms in blue. The heavy
chain of DH270 UCA is shown in green and light chain in yellow. Color code for
complementarity-determining regions (CDRs) of the antibody: wheat, CDR H1; blue,
CDRH2;purple,CDRH3;brown,CDRL1;pink,CDRL2;teal,CDRL3.DH270UCA
contacted the V1 loop, the V3 loop, and the surrounding glycans, with contacts made
by both the heavy and light chains of the antibody. (FtoH) Zoomed-in views of the
structure showing details of the contacts DH270 UCA makes with glycan 332,
shown in stick representation overlaid with dots and colored by element, with the
DH270 UCA shown in surface representation (F), the V3 loop (G), and the V1 loop (H).RESEARCH | RESEARCH ARTICLE
on December 12, 2019^http://science.sciencemag.org/Downloaded from