Table 2.

Refinement statistics for streptavidin mutants `1' and `2'

Mutant	apo-SAm1	SAm1•StrepII	apo-SAm2	SAm2•StrepII
R-factor/RFree	17.0/22.9	17.5/21.7	19.1/22.8	17.8/22.1
Protein residues	478	480	478	480
Protein residues visible	A16–A135	A16–A136	A16–A135	A16–A136
	B15–B134	B15–B134	B15–B134	B15–B134
	C16–C134	C15–C134	C16–C134	C15–C134
	D16–D134	D16–D134	D16–D134	D16–D134
Ligand residues	—	24	—	22
Ligand residues visible		E3–E8		E3–E7
		F4–F9		F4–F8
		G4–G9		G4–G9
		H4–H9		H4–H9
No. of solvent molecules	212	240	195	167
R.m.s. deviations from ideality of bond lengths	0.016 Å	0.018 Å	0.018 Å	0.017 Å
R.m.s. deviations from ideality of bond angles	2.868°	2.773°	2.548°	2.679°
Average B-values:
whole molecule	27.5 Å2	27.3 Å2	25.1 Å2	24.4 Å2
residues 46–51	48.6 Å2	43.2 Å2	47.4 Å2	41.8 Å2
peptide ligand	—	33.1 Å2	—	35.1 Å2
PDB accession code	1kff	1kl3	1kl4	1kl5