Nonribosomal peptide synthetase; part of the gene cluster that mediates the biosynthesis of verlamelin, a lipopeptide that exhibits antifungal activity against plant pathogenic fungi (PubMed:24848421). Verlamelin is a cyclic hexadepsipeptide and is bridged by ester bonding between a 5-hydroxytetradecanoic acid moiety and a carboxyl group on the terminal Val of amide-bonded tetradecanoyl-hexapeptide D-allo-Thr-D-Ala-L-Pro-L-Gln-D-Tyr-L-Val (PubMed:24848421). VlmA and vlmB are altogether regarded as essential components in the biosynthesis of 5-hydroxytetradecanoic acid (PubMed:24848421). VlmA catalyzes the hydroxylation at position C5 of tetradecanoic acid produced in primary metabolism, while the precise function of vlmB still remains to be solved (PubMed:24848421). To be loaded onto the waiting NRPS, 5-hydroxytetradecanoic acid is activated in the form of acyladenylate by the AMP-dependent ligase vlmC (PubMed:24848421). VlmS seems to accept the fatty-acyl intermediate onto the initial module to further elongate amino acid residues by the downstream modules (PubMed:24848421). In addition, in the last module at its C-terminus, vlmS contains a surplus condensation (C) domain that may be involved in cyclization, the last step to form verlamelin (PubMed:24848421). Secondary metabolite biosynthesis. NRP synthetases are composed of discrete domains (adenylation (A), thiolation (T) or peptidyl carrier protein (PCP) and condensation (C) domains) which when grouped together are referred to as a single module (PubMed:24848421). Each module is responsible for the recognition (via the A domain) and incorporation of a single amino acid into the growing peptide product. Thus, an NRP synthetase is generally composed of one or more modules and can terminate in a thioesterase domain (TE) that releases the newly synthesized peptide from the enzyme. Occasionally, epimerase (E) domains (responsible for l- to d-amino acid conversion) are present within the NRP synthetase. VlmS has the following 7 module architecture: T-E-C-A-T-E-C-A-T-E-C-A-T-C-A-T-C-A-T-E-C-A-T-C (PubMed:24848421). The epimerase domain in the first module is probably non-functional (PubMed:24848421). Leads to complete loss of verlamelin production (PubMed:24848421). Belongs to the NRP synthetase family.