Reconstitution of the Final Steps in the Biosynthesis of Valanimycin Reveals the Origin of Its Characteristic Azoxy Moiety

• DOI: 10.1002/ange.202315844
• Publication Date: 2023-11-15T03:29:33Z
• Authors: Ziyang Zheng; Jin Xiong; Junling Bu; Daan Ren; Yu‐Hsuan Lee; Yu‐Cheng Yeh; Chia‐I Lin; Ronald Parry; Yisong Guo; Hung‐wen Liu
• Keywords: Azoxy; Moiety; Hydroxylamine

Abstract Valanimycin is an azoxy‐containing natural product isolated from the fermentation broth of Streptomyces viridifaciens MG456‐hF10. While biosynthesis valanimycin has been partially characterized, how azoxy group constructed remains obscure. Herein, membrane protein VlmO and putative hydrazine synthetase ForJ formycin biosynthetic pathway are demonstrated to catalyze N−N bond formation converting O ‐( l ‐seryl)‐isobutyl hydroxylamine into N ‐(isobutylamino)‐ ‐serine. Subsequent installation shown be catalyzed by non‐heme diiron enzyme VlmB in a reaction which single VlmO/ForJ oxidized four electrons yield group. The catalytic cycle appears begin with resting μ‐oxo diferric complex VlmB, as supported Mössbauer spectroscopy. This study also identifies d ‐serine alternative substrate for leading two regioisomers. reactions kinase VlmJ lyase VlmK during final steps established well. was thus fully reconstituted vitro using enzymes VlmO/ForJ, VlmK. Importantly, VlmB‐catalyzed represents first example enzyme‐catalyzed expected proceed atypical mechanism.