TABLE 1.

In vivo photocross-linking of secA(Am) mutants to SecY

E. coli secA(Am) residuea	T. maritima residueb	SecA domainc	X-linking resultd	Mobility of SecA·SecY complexe
59	52	NBD-I	+	F
104	97		−	NA
226	269	PPXD	W	S
233	276		+	S
256	288		W	S
265	297		−	NA
300	325		+	S
334	359		−	NA
340	365		+	F
344	369		−	NA
350	375		+	F
423	448	NBD-II	W	F
427	452		+	F
447	472		+	F
458	483		+	F
518	NA		W	F
530	NA		+	F, S
597	596		−	NA
600	599		+	F
640	636	HSD	+	S
656	652		+	F
661	657		+	F, S
753	749	HWD	−	NA
833	NA	CTD	+	F, S
858	NA		+	F, S
896	NA		+	S

^a The indicated secA amber mutant was grown and subjected to photocross-linking analysis as described under “Experimental Procedures.”

^b Indicates the homologous residue of E. coli SecA for T. maritima SecA.

^c Indicates the SecA domain location of each Bpa-labeled SecA residue.

^d + or − or W indicates that a positive or negative or weakly positive photocross-linkzng result was obtained for the indicated secA(Am) mutant based on the intensity of any SecA-SecY species observed. Representative data from a number of repetitions are shown in supplemental Fig. S2.

^e F or S indicates faster or slower electrophoretic mobility of the indicated SecA·SecY complex; R_f values of 0.57 ± 0.03 and 0.36 ± 0.02, respectively, were obtained in this case relative to phosphorylase b, which was used as an internal standard. NA indicates “not applicable.”