Close-up view of areas around the amino acids 364 (A) and 510 (B). Residues in close contact with the mutated residues, translated from codons 364 and 510, are shown with side chains, whereas the residues further apart are shown in Cα-ribbon trace representation as in Fig 4. The color code is as for Fig 1. (A) and (B) are shown with the mutated aspartic acid and glutamine replacing the wild-type glycine and arginine, respectively. Hydrogen bonds less than 3.0 Å are shown as white lines.