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Active-site cavities are shown as semitransparent surfaces for apo 3A5 (A), 3A5 ritonavir complex (B), apo 3A4 (C), and 3A4 ritonavir complex (D) with adjacent amino acid side chains, the heme co-factor, and ritonavir are shown as stick models. Amino acid residues that differ between 3A4 and 3A5 are identified by bold labels. The viewpoint and scale are identical for each image.
