Table 3.

Proposed and the main activated substrates, the 10 amino acid residues predicted to line the substrate binding pocket of the NpnA, NpnB, and NpnC adenylation domains, and predicted substrates determined through precedence in other NRPS proteins (17)^a

NRPS module	Proposed substrate	Activated substrate	% match	Amino acid at residue:
				235	236	239	278	299	301	322	330	331	517
NpnA1	PheAc-CoA	HClN	100	V	G	V	W	V	A	A	S	G	K
NpnB1	Gln	Gln	100	D	A	W	L	F	G	L	I	D	K
NpnB2	Gly	Gly	100	D	I	L	A	L	G	L	I	W	K
NpnC1	Pro	Pro	100	D	V	Q	F	I	A	H	V	V	K
NpnC2	Phe	Phe	100	D	A	W	T	I	A	A	V	C	K
NpnC3	Ile	l-allo-Ile	100	D	A	F	F	L	G	V	T	F	K
NpnC4	Pro	Pro	100	D	V	Q	F	I	A	H	V	V	K

^aPheAc-CoA, phenylacetate coenzyme A; HClN, hydrocinnamic acid.