397 CYS SG 400 CYS SG 3.55 397 CYS SG 413 HIS NE2 3.25 397 CYS SG 417 CYS SG 3.55 400 CYS SG 413 HIS NE2 3.25 400 CYS SG 417 CYS SG 3.55 413 HIS NE2 417 CYS SG 3.25