TABLE 3.

Predicted BT NRPS module substrate specificities and refinement of the BT1583 peptide structure

Module	Amino acid at PheA residuea:										Predicted substrate specificity	Partial BT1583 sequence	Refined BT1583 sequence
	235	236	239	278	299	301	322	330	331	517
1	D	F	W	N	I	G	M	V	H	K	Thr/Dht	(CH3)2-Bmt?b	(CH3)2-Bmt?
2	D	G	F	L	L	G	G	V	F	K	Ile/Leu	Leu/Ile	Leuc
3	D	S	G	P	S	G	A	V	D	K		Ornb	Orn
4	D	G	F	F	L	G	V	V	Y	K	Ileb	Leu/Ile	Ile
5	D	G	F	F	V	G	G	V	F	K	Ile/Leu/Val	Valb	Val
6	D	G	F	F	V	G	G	V	F	K	Ile/Leu/Val	Valb	Val
7	D	A	G	P	S	G	A	V	D	K		Lysb	Lys
8	D	G	F	F	V	G	G	V	F	K	Ile/Leu/Val	Valb	Val
9	D	A	W	F	L	G	N	V	V	K	Leub	Leu/Ile	Leu
10	D	A	G	P	S	G	A	V	G	K		Lysb	Lys
11	D	A	A	A	V	V	G	V	A	K	Phe/Trp/Tyr	Tyrb	Tyr
12	D	A	W	F	L	G	N	V	W	K	Leub	Leu/Ile	Leu
13	D	G	F	F	A	G	G	V	F	K	Ile/Leu/Val	Val-CH2OHb	Val-CH2OH

^aThe residues were numbered according to the corresponding residues of PheA (4).

^bThe information was used for BT1583 peptide sequence refinement.

^cThe Leu at this position was deduced from the fact that the only Ile had been assigned to position 4.