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. 2011 Nov;85(22):11725–11731. doi: 10.1128/JVI.05680-11

Fig. 2.

Fig. 2.

2F5 UAs bind to 2F5 nominal epitope peptide with weaker affinity than 2F5 MAb. The gp41 MPER peptide (QQEKNEQELLELDKWASLWN), which includes the 2F5 nominal epitope peptide, was anchored (200 to 300 RU) on a streptavidin (SA) chip via a biotin tag attached to the N terminus of the peptide. Each MAb was injected at various concentrations: 0.67, 1.7, 3.3, 6.7, 13.3, and 26.7 nM (2F5) (A); 3.3, 6.7, 13.3, and 33.3 nM (2F5 UA variant 1) (B); and 66.7, 165.7, 333.3, and 500 nM (2F5 UA variant 2) (C). UA variant 1 with HCDR2 DH54 bound to gp41 MPER peptide with a 40-fold-higher binding Kd than that of UA variant 2 (NH54). Rate constants, ka and kd, for 2F5 were 1.97 × 105 M−1 s−1 and 8.8 × 10−4 s−1; those for UA variant 1 were 3.0 × 105 M−1 s−1 and 3.26 × 10−2 s−1; those for UA variant 2 were 8.4 × 103 M−1 s−1 and 4.1 × 10−2 s−1, respectively. Data are representative of at least two independent experiments.