TABLE 1.

Summary of results for disulfide cross-linked cysteine pairs R334C/T1122C, R334C/G1127C, and T338C/S1118C

Cysteine pairs were studied with either the native Glu present at position 1371 (Glu-1371) or with Gln substituted at this position (Gln-1371). As described under “Discussion,” Glu-1371 is expected to reflect both open and closed channels, and Gln-1371 reflects almost exclusively open channels. In parentheses are indicated the figures in which the quantitative evidence justifying each nonquantitative statement in the table is presented.

	R334C/T1122C		R334C/G1127C		T338C/S1118C
	Glu-1371	Gln-1371	Glu-1371	Gln-1371	Glu-1371	Gln-1371
Spontaneous cross-linking	No (Figs. 1 and 3)	Yes (Fig. 6)	Yes (Figs. 1 and 3)	No (Fig. 6)	No (Figs. 1 and 3)	No (Fig. 6)
CuPhe-induced cross-linking	Yes (Fig. 1)	Yes (Fig. 4)	Yes (Fig. 1)	No (Fig. 4)	Yes (Fig. 1)	Enhanced (Fig. 4)
Cd2+ inhibition	Strong (Fig. 3)	Strong (Fig. 5)	Moderate (Fig. 3)	Abolished (Fig. 5)	Weak (Fig. 3)	Strengthened (Fig. 5)