view article
Figure 5
Sequence and structural comparison of hRV-B14, hRV-A16 and hRV-A21 3C proteases. (A) Sequence alignment of hRV-B14, hRV-A16 and hRV-A21 3C proteases. Conserved residues are shaded in gray and black, and variable regions (VR1: residues 91–97; VR2: residues 97–110) are highlighted with blue boxes. Red arrows indicate interacting residues. (B) Structural superposition of hRV-B14 (green), hRV-A16 (pink; AlphaFold-predicted model) and hRV-A21 (light blue; AlphaFold-predicted model) 3C proteases. Variable region 1 (blue box) is positioned opposite the active site (green circle) and variable region 2 (orange box) is located near the substrate-binding cleft. (C) A close-up view of variable region 2 (orange box) and the catalytic loop (red arrow) of hRV-B14 (green) and hRV-A21 (light blue) 3C proteases. The key residues of hRV-B14 3C protease are denoted without parentheses, whereas hRV-A21 3C protease residues are shown in parentheses.

IUCrJ
Volume 13| Part 1| January 2026| Pages 19-30
ISSN: 2052-2525
https://doi.org/10.1107/S2052252525008929