# List two residues never to be in contact. 4 HIS 11 HIS 4 HIS 12 HIS 4 HIS 13 HIS 5 HIS 12 HIS 5 HIS 13 HIS 5 HIS 14 HIS 7 HIS 20 HIS 7 HIS 21 HIS 7 HIS 22 HIS 7 HIS 23 HIS 7 HIS 24 HIS 8 HIS 20 HIS 8 HIS 21 HIS 8 HIS 22 HIS 8 HIS 23 HIS 8 HIS 24 HIS 11 HIS 19 HIS 11 HIS 22 HIS