Involved in the synthesis of the siderophore vanchrobactin (PubMed:17159203). Probably adenylates L-arginine via its first adenylation domain and loads it onto its first peptidyl carrier domain via a thioester linkage to the phosphopanthetheine moiety. In addition, may adenylate L-serine via its second adenylation domain and loads it onto its second peptidyl carrier domain via a thioester linkage to the phosphopanthetheine moiety (Probable). The thioesterase domain may release vanchrobactin after condensation of the siderophore components (Probable). ATP + holo-[peptidyl-carrier protein] + L-arginine = AMP + diphosphate + L-arginyl-[peptidyl-carrier protein] ATP + holo-[peptidyl-carrier protein] + L-serine = AMP + diphosphate + L-seryl-[peptidyl-carrier protein] Siderophore biosynthesis. Modular protein that contains two adenylation domains which activate the amino acids into aminoacyl-AMP esters, two peptidyl carrier protein domains which bear a phosphopantetheinyl arm to attach the activated amino acids, three condensation domains and a thioesterase domain that may release the newly synthesized peptide from the enzyme. Mutant can still produce DHBA, but not vanchrobactin. Mutant is significantly impaired for growth under iron-limited conditions, and siderophore levels in supernatants are less than 20% of those detected in the parental strain. Belongs to the NRP synthetase family.