Streptomyces wadayamensis MppP Is a Pyridoxal 5′-Phosphate-Dependent l-Arginine α-Deaminase, γ-Hydroxylase in the Enduracididine Biosynthetic Pathway

Abstract

L-Enduracididine (L-End) is a nonproteinogenic amino acid found in a number of bioactive peptides, including the antibiotics teixobactin, enduracidin, and mannopeptimycin. The potent activity of these compounds against antibiotic-resistant pathogens like MRSA and their novel mode of action have garnered considerable interest for the development of these peptides into clinically relevant antibiotics. This goal has been hampered, at least in part, by the fact that L-End is difficult to synthesize and not currently commercially available. We have begun to elucidate the biosynthetic pathway of this unusual building block. In mannopeptimycin-producing strains, like Streptomyces wadayamensis, L-End is produced from L-Arg by the action of three enzymes: MppP, MppQ, and MppR. Herein, we report the structural and functional characterization of MppP. This pyridoxal 5'-phosphate (PLP)-dependent enzyme was predicted to be a fold type I aminotransferase on the basis of sequence analysis. We show that MppP is actually the first example of a PLP-dependent hydroxylase that catalyzes a reaction of L-Arg with dioxygen to yield a mixture of 2-oxo-4-hydroxy-5-guanidinovaleric acid and 2-oxo-5-guanidinovaleric acid in a 1.7:1 ratio. The structure of MppP with PLP bound to the catalytic lysine residue (Lys221) shows that, while the tertiary structure is very similar to those of the well-studied aminotransferases, there are differences in the arrangement of active site residues around the cofactor that likely account for the unusual activity of this enzyme. The structure of MppP with the substrate analogue D-Arg bound shows how the enzyme binds its substrate and indicates why D-Arg is not a substrate. On the basis of this work and previous work with MppR, we propose a plausible biosynthetic scheme for L-End.

Emergence of oxygen‐ and pyridoxal phosphate‐dependent reactions

“…The amino acid l ‐arginine has emerged as a common substrate for sequence‐related oxygen‐dependent PLP enzymes from Streptomyces bacteria. These enzymes include Ind4 from the indolmycin biosynthetic pathway [71,72], MppP from enduracididine biosynthesis [73,74], and RohP from the azomycin biosynthetic pathway [75,76]. Indolmycin, enduracididine, and azomycin each contain arginine‐derived heterocycles, for which Ind4, MppP, and RohP are essential upstream enzymes toward the biosynthesis of each heterocycle.…”

Chemistry and Biology of Teixobactin

“…[18] Biochemical ands tructural studies showed that MppP is aP LP-dependent hydroxylase, which catalyzes the conversion of l-Arg and dioxygen to produce 2-oxo-4-hydroxy-5-guanidinovaleric acid (1)( Figure 5). [19] MppR shares ah igh degree of structurals imilarity with acetoacetate decarboxylase, which converts 1 to 3-[(4R)-2-iminoimidazolidin-4-yl]-2-oxopropanoic acid (2), the ketone form of l-End. [20] The PLP-dependenta minotransferase MppQ then catalyzes the reductivea mination of 2 to produce l-End ( Figure 5).…”

Nicht‐ribosomale Peptidsynthese – Prinzipien und Perspektiven

“…Strukturell noch ungewöhnlicher sind die cyclischen Arg‐Analoga Enduracididin (End), bekannt von Mannopeptimycin, sowie das Capreomycidin (Cap), ein Bestandteil von Peptiden der Tuberactinomycin‐Gruppe wie des Viomycins. Für End wie auch für Cap (Schema a) wird Arg als Ursprung vorgeschlagen. Einiges deutet darauf hin, dass β‐Cyanalanin (Cya) ATP‐abhängig nach einem NRPS‐gebundenen Mechanismus durch Dehydratisierung aus Asn synthetisiert wird .…”