Table II.

Summary of NMR Titration Experiments of hCXCR1Ndp Binding to CXCL8 Variants

Complex	Buffer conditions	Temp	CXCL8 conc. Start/end (μM)c	Final Peptide Conc. (μM)	Molar ratio	FB (%)	Kd (μM)d
WT + h29mera,b	50 mM Pi, pH 7.0	30°C	90/62	711	1:11.5	87 ± 2	103 ± 12
WT + h29mera,b	50 mM Pi, pH 6.0	30°C	100/80	850	1:10.5	98 ± 1	17 ± 4
WT + h21mera,b	50 mM Pi, 150 NaCl, pH 6.5	25°C	125/20	2660	1:134	79 ± 3	700 ± 90
R26C + h29mer	50 mM Pi, pH 7.0	30°C	150/129	1029	1:11.2	85 ± 3	172 ± 24
1–66 monomer + h29mer	50 mM Pi, pH 6.0	30°C	200/135	1135	1:8.4	>99	<5
V27P/E29P monomer + h29mer	50 mM Pi, pH 7.0	30°C	100/65	777	1:11.9	>99	<5
V27P/E29P monomer + h21mer	50 mM Pi, pH 7.0	30°C	100/72	461	1:6.4	90 ± 3	43 ± 10
V27P/E29P monomer + h21mer	50 mM Pi, 150NaCl, pH 6.5	25°C	100/69	945	1:13.8	88 ± 2	118 ± 14
L25Y/V27R monomer + h21mer	50 mM Pi, pH 7.0	30°C	100/63	506	1:8	77 ± 5	135 ± 25
L25Y/V27R monomer + h21mer	50 mM Pi, 150 NaCl, pH 6.5	25°C	150/62	1176	1:19	72 ± 2	432 ± 25

^aWT dimer dissociation was coupled to receptor peptide binding

^bK_d calculated for the dimer.

^cConcentrations are reported in monomer units.

^dK_d values are averages calculated from a subset of 8–15 residues; Pi, phosphate.