Table 1.

Dissociation Constants for Ligand Binding to Single Trp Mutants of Human Tear Lipocalin

β-strand or loop	mutant	Kd (μM), C12SL	Kd (μM), C16
β-strand A	W22	0.4 ± 0.1	0.9 ± 0.2
β-strand A	W24	0.4 ± 0.1	naa
loop AB	W25	0.5 ± 0.1	na
loop AB	W26	1.6 ± 0.2	na
loop AB	W27	2.5 ± 0.1	na
loop AB	W28	0.4 ± 0.2	0.7 ± 0.4
loop AB	W30	0.5 ± 0.1	na
loop AB	W33	5.9 ± 0.4	na
loop AB	W34	0.4 ± 0.1	na
loop AB	W35	3.5 ± 0.3	na
loop AB	W36	0.4 ± 0.1	na
loop AB	W37	4.7 ± 0.5	5.8 ± 0.6
β-strand B	W39	3.1 ± 0.3	na
β-strand B	W41	na	na
β-strand C	W49	2.4 ± 0.2	2.3 ± 0.2
β-strand C	W53	0.3 ± 0.1	na
β-strand C	W55	0.3 ± 0.1	na
β-strand C	W57	0.5 ± 0.1	0.5 ± 0.1
β-strand D	W60	1.9 ± 0.5	na
β-strand D	W62	0.3 ± 0.1	na
β-strand D	W64	0.3 ± 0.1	na
β-strand D	W66	0.3 ± 0.1	na
β-strand D	W68	0.7 ± 0.1	0.3 ± 0.1
β-strand E	W77	1.0 ± 0.5	na
β-strand E	W79	0.5 ± 0.1	na
β-strand E	W80	0.9 ± 0.4	na
β-strand F	W84	0.5 ± 0.1	na
β-strand F	W86	1.0 ± 0.3	na
β-strand F	W88	0.5 ± 0.2	0.5 ± 0.2
β-strand G	W97	0.4 ± 0.1	0.4 ± 0.1
β-strand G	W99	0.3 ± 0.1	na
β-strand G	W101	0.4 ± 0.2	2.8 ± 0.5
β-strand G	W103	0.3 ± 0.1	0.3 ± 0.1
β-strand G	W105	0.5 ± 0.1	0.5 ± 0.1
β-strand H	W110	0.7 ± 0.1	na
β-strand H	W112	0.4 ± 0.1	na
β-strand H	W114	0.4 ± 0.1	1.1 ± 0.6
β-strand H	W116	0.5 ± 0.2	na

^aNot applicable due to the absence of quenching.