Figure 7.

Key interactions of PG16 residues H100R and D101. (A) Interaction of H100R with the MAN4 glycan of gp120 (black dotted line). (B,C) Shortest distance between the H100R imidazole ring and the MAN4 glycan in (B) TYS-PG16 and (C) TYR-PG16 (run1, blue; run2, orange). Explicit values are highlighted as dots and running averages are shown as lines. (D) Interaction of D101 with the MAN7 glycan of gp120. (E,F) Shortest distance between the D100 carboxyl oxygens and the hydroxy groups of the MAN7 glycan (E) TYS-PG16 and (F) TYR-PG16 (run1, blue; run2, orange). The two shades of blue and orange indicate the interactions of the individual oxygens, O$\mathsf{\delta }$1 and O$\mathsf{\delta }$2. The black dotted line marks a distance of $2.5$Å, as the upper limit for the formation of a hydrogen bond (measured between the oxygen atom as the donor and hydrogen atom as the hydrogen bond acceptor).