FIG 1.

Design and evaluation of a new combination of proline stabilization mutations in gp41. (A) Left, a single monomer of gp41 in the prefusion conformation (PDB ID: 6VZI) is shown as white ribbons. Residues that were targeted for proline stabilization are shown as colored sticks surrounded by a transparent molecular surface. Right, a single monomer of gp41 in the postfusion conformation (homology model based on PDB ID 7AEJ) is shown and is colored according to the prefusion monomer. (B) Size-exclusion chromatograms from a Superose 6 Increase column for each individual mutant after affinity chromatography are overlaid; mAU, milli-absorbance unit. (C) Size-exclusion chromatograms from a Superose 6 Increase column are shown for individual proline mutants and are colored either blue or red. The combination of the two mutations is colored purple, and the unmutated CH848 10.17DT DS-SOSIP is colored black and labeled “WT.” (D) Representative negative stain EM 2D class averages of CH848 10.17DT DS-SOSIP L568P and T569P (calculated in Relion 3.0) are shown.