Table 2. Characterization of NRPS- or PKS-encoding genes identified by antiSMASH (Blin et al., 2013).

Gene cluster	Genomic region predicted by antiSMASH	Enzyme predicted by antiSMASH	Gene(s) encoding NRPS (or NRPS-PKS)	Previously reported product	Putative product	Comments
1	SMA1552–1589	NRPS	SMA1571-1572	–	Unknown	*
2	SMA1705–1744	NRPS	SMA1729	–	Siderophore	†
3	SMA2274-1309	NRPS-PKS	SMA2289-2290	Althiomycin	na	‡
4	SMA3659–3702	NRPS	SMA3680	Serrawettin W2	na	§
5	SMA4386–4438	NRPS	SMA4411	–	Siderophore	||
SMA4402-4404, SMA4406	–	Unknown	¶

na, not applicable.

^*Predicted NRPS encoded within a cluster of genes (SMA1575–1568) showing similarity with genes involved in the biosynthesis and secretion of microcins; may synthesize a modifying group added to the microcin.

^†Predicted NRPS similar to chrysobactin synthetase (64 % identity over the whole length) and flanked by genes encoding proteins with similarity to proteins mediating siderophore export, uptake and iron release.

^‡Althiomycin is a broad-spectrum antibiotic. NRPS-PKS is encoded within the six-gene alb operon (SMA2288–2293), which also encodes tailoring and export functions (Gerc et al., 2012).

^§Serrawettin W2 is a biosurfactant (Pradel et al., 2007).

||Predicted NRPS is similar to enterobactin synthetase EntF and within cluster of genes (SMA4408–4415) similar to the enterobactin biosynthesis, export and uptake cluster of E. coli (Fig. 3).

^¶Encoded NRPS proteins share similarity with siderophore synthetase enzymes from other organisms but number and nature of product(s) unclear.