Aminoacyl sulfonamide assembly in SB-203208 biosynthesis

Abstract

Sulfonamide is present in many important drugs, due to its unique chemical and biological properties. In contrast, naturally occurring sulfonamides are rare, and their biosynthetic knowledge are scarce. Here we identify the biosynthetic gene cluster of sulfonamide antibiotics, altemicidin, SB-203207, and SB-203208, from Streptomyces sp. NCIMB40513. The heterologous gene expression and biochemical analyses reveal unique aminoacyl transfer reactions, including the tRNA synthetase-like enzyme SbzA-catalyzed L-isoleucine transfer and the GNAT enzyme SbzC-catalyzed β-methylphenylalanine transfer. Furthermore, we elucidate the biogenesis of 2-sulfamoylacetic acid from L-cysteine, by the collaboration of the cupin dioxygenase SbzM and the aldehyde dehydrogenase SbzJ. Remarkably, SbzM catalyzes the two-step oxidation and decarboxylation of L-cysteine, and the subsequent intramolecular amino group rearrangement leads to N-S bond formation. This detailed analysis of the aminoacyl sulfonamide antibiotics biosynthetic machineries paves the way toward investigations of sulfonamide biosynthesis and its engineering.

Characterization of the nonheme iron center of cysteamine dioxygenase and its interaction with substrates

“…The observation of a DNIC in ADO in the presence of primary substrate leads to the interpretation that both oxygen atoms of molecular oxygen could spontaneously bind to the iron center, forming an octahedral ternary complex after monodentate thiolate ligation. If so, our findings here add a new, side-on oxygen binding model to the thiol dioxygenase family, because previously binding modes were exclusively proposed as end-on (5,8,28,54,58,65). A new oxygen binding mode potentially represents a new oxygen activation mechanism during thiol oxidation and Cys-Tyr cross-link biogenesis in thiol dioxygenases.…”

“…Additionally, SbzM and OvoA are two nonheme iron enzymes related to cysteine oxidation but are not yet classified as thiol dioxygenases because of their atypical reactions and different metal ligands. SbzM catalyzes the two-step oxidation and decarboxylation of cysteine (54), whereas OvoA promotes either dioxygenation or dimerization of cysteine as modulated by histidine (55). The substrate binding of neither enzyme has been spectroscopically characterized.…”

Biosynthesis of the N–N‐Bond‐Containing Compound l‐Alanosine

“…The use of a cupin domain for NÀN bond formation, as in the case of SznF, is emerging as potentially widespread strategy toward diverse N À N bonds, as well as other heteroatom-heteroatom linkages, like sulfonamides. [11] In addition to the streptozocin pathway, cupin-domain-encoding genes have now been linked to natural products that contain NÀN bonds, including pyrazomycin, [12] hydrazinoacetic acid, [13] triacsins, [14] fragin, [15] and gramibactin, [16] even though the exact mechanistic details are not fully understood (Figure 1 a). Among the diazeniumdiolates, which tautomerize to N-hydroxy-N-nitroso compounds (Figure 1 b), [17,18] both fragin and gramibactin have been linked to cupin-domaincontaining genes through gene inactivation studies.…”

Engineered Biosynthesis of Pharmaceutically Important Compounds

“…Thus, we focused on the putative self-resistant IleRS gene to find the gene cluster of SB-203208 in the genome sequence, rather than relying on the enzyme similarity. 18) As a result, we found two copies of Ile-RS genes, and one of them (sbzA) was clustered with non-ribosomal peptide synthetase (NRPS) and sugar metabolite genes. 19) We named this gene cluster the sbz cluster, and expressed the genes in two operons (sbz-1 and -2) in Streptomyces lividans using two vectors with different phageintegration sites.…”