Table I.

Sequence alignment^a and effects of MTSET on channels with engineered cysteines^b

Channel	Segment		No.	1	11	21
KcsA	M1	o	23	ALHWRAAGAA	TVLLVIVLLA	GSYLAVLAER
Kv1.2	S5	o	322	KASMRELGLL	IFFLFIGVIL	FSSAVYFAEA
Cav2.1	IS5	1o	220	MKAMIPLLQI	GLLLFFAILI	FAIIGLEFYM
	IIS5	2o	608	LNSMKSIISL	LFLLFLFIVV	FALLGMQLFG
	IIIS5	3o	1380	VNSLKNVFNI	LIVYMLFMFI	FAVVAVQLFK
	IVS5	4o	1695	VQSFKALPYV	CLLIAMLFFI	YAIIGMQVFG
Pore-facing position				* *	* *
				1	11	21	31
KcsA	M2	i	86	LWGRLVAVVV	MVAGITSFGL	VTAALATWFV	GREQ
Kv1.2	S6	i	385	IGGKIVGSLC	AIAGVLTIAL	PVPVIVSNFN	YFYH
Cav2.1	IS6	1i	336	TWNWLYFIPL	IIIGSFFMLN	LVLGVLSGEF	AKER
	IIS6	2i	690	MVFSIYFIVL	TLFGNYTLLN	VFLAIAVDNL	ANAQ
	IIIS6	3i	1485	MEMSIFYVVY	FVVFPFFFVN	IFVALIIITF	QEQG
	IVS6	4i	1785	EFAYFYFVSF	IFLCSFLMLN	LFVAVIMDNF	EYLT
Nav1.4	IVS6	4i	1565	SIGICFFCSY	IIISFLIVVN	MYIAIILENF	NVAT
Pore-facing position					* * **	** **
Cytoplasm-facing position						** *** *	*

Data for Na_v1.4 are from (Sunami et al., 2004).

^aShown alignments of S5 (Huber et al., 2000) and S6 (Zhorov et al., 2001) segments were used to build the Ca_v2.1 models.

^bBold-oblique and underlined characters indicate positions where MTSET inhibits channels with engineered cysteines ≥30 and <30%, respectively (Zhen et al., 2005).