. 2004 Nov;186(22):7499–7507. doi: 10.1128/JB.186.22.7499-7507.2004

TABLE 2.

Effects of amino acid changes in CzcD and ZitB and corresponding positions in either protein

CzcD				ZitB
Change	Effect	IC₅₀ of Zn²⁺ (μM)^a	b (μM)^b	Change	Effect	IC₅₀ of Zn²⁺ (μM)^a	b (μM)^b
None	Wild-type CzcD	204 ± 3	46	None	Wild-type ZitB	736 ± 114	146
Control	No CzcD	108 ± 9^c	55	Control	No ZitB	105 ± 48^d	114
ΔC terminus^e^,^f				ΔC terminus	No function	122 ± 51	41
H5R	Partially active^g	163 ± 30	38	H3^h
H7R	No function	105 ± 1	38	H5^h
H9R	Partially active	154± 65	42	H7^h
H49R	Not expressed	NDⁱ		H53R	No function	241 ± 178	108
H49A	No function	104 ± 4	30	H53^h
H237R	No function	118 ± 18	36	H243^h
H251R	Not expressed	ND		H256^h
H251A	Partially active	137 ± 12	60	H256^h
H280R	Not expressed	ND		H254^h
H280A	No function	93 ± 15	40	H284^h
H298R	Not expressed	ND		N302^h
H298A	No function	102 ± 7	45	N302^h
C290S	HyperSensitive^j	78 ± 0	45	C294S	Wild type	554 ± 341	117
E31D	Partially active	125 ± 7	36	E35^h
E31N	Not expressed	ND		E35^h
E31K	No function	125 ± 7	31	E35^h
E154D	No function	116 ± 12	34	H159E	No function	173 ± 34	73
E154N	No function	100 ± 13	31	H159R	No function	213 ± 69	156
E209^f				E214A	No function	90 ± 48	183
D46^f				D50E	Partially active	209 ± 19	72
D46^f				D50A	No function	149 ± 17	77
D53E	Hypersensitive	60 ± 2	29	D57^h
D53A	Hypersensitive	56 ± 6	47	D57A	No function	148 ± 17	77
D53N	Hypersensitive	48 ± 7	26	D57^h
D158A	No function	85 ± 6	77	D163A	No function	192 ± 43	101
D158E	No function	112 ± 19	22	D163E	No function	122 ± 29	121
D181E	Hypersensitive	76 ± 61	56	D186E	Partially active	210 ± 33	75
D181N	Hypersensitive	59 ± 1	19	D186^h
D181A	Partially active	136 ± 80	59	D186A	No function	102 ± 34	86
M5OL	Hypersensitive	63 ± 7	40	M54L	Partially active	286 ± 95	96
R108^f				R112A	Wild type	744 ± 172	172
N130^f				N135A	No function	168 ± 27	70
S162^f				S167A	No function	127 ± 19	45
F174^f				W182L	Partially active	201 ± 31	68
W239^f				W245L	Partially active	461 ± 125	103

IC₅₀, 50% inhibitory concentration (zinc concentration required to decrease the cell density of the growing culture to one-half the positive control value with no added zinc). Values are given with standard deviations.

b is the slope of the sigmoidal dose-response curve.

Value determined in Halle, Germany, for CzcD experiments.

Value determined in Tuczon, Ariz., for ZitB experiments.

ΔC terminus, deletion of the carboxy terminus.

Site that was not changed in CzcD but was changed in ZitB.

The phenotype was partially active if the IC₅₀ of the wild type minus deviation was greater than the IC₅₀ of the mutant plus deviation and the IC₅₀ of the mutant minus deviation was less than the IC₅₀ of the vector control plus deviation.

Site that was changed in CzcD but was not changed in ZitB.

ⁱ

ND, not determined.

The phenotype was hypersensitive if the IC₅₀ of the mutant plus deviation was less than the IC₅₀ of the vector control minus deviation.