Unveiling sequential late-stage methyltransferase reactions in the meleagrin/oxaline biosynthetic pathway

Autor(es)

Newmister, Sean A. ^[1] ; Romminger, Stelamar ^[1] ; Schmidt, Jennifer J. ^[1] ; Williams, Robert M. ^{[2, 3]} ; Smith, Janet L. ^{[1, 4]} ; Berlinck, Roberto G. S. ^[5] ; Sherman, David H. ^{[6, 1, 7, 8]}

Afiliação do(s) autor(es)

^[1] Univ Michigan, Inst Life Sci, Ann Arbor, MI 48109 - USA

^[2] Colorado State Univ, Dept Chem, Ft Collins, CO 80523 - USA

^[3] Univ Colorado, Ctr Canc, Aurora, CO 80045 - USA

^[4] Univ Michigan, Dept Biol Chem, Ann Arbor, MI 48109 - USA

^[5] Univ Sao Paulo, Inst Quim Sao Carlos, CP 780, BR-13560970 Sao Carlos, SP - Brazil

^[6] Univ Michigan, Dept Chem, Ann Arbor, MI 48109 - USA

^[7] Univ Michigan, Dept Med Chem, Ann Arbor, MI 48109 - USA

^[8] Univ Michigan, Dept Microbiol & Immunol, Ann Arbor, MI 48109 - USA

• Tipo de documento: Artigo Científico
• Fonte: ORGANIC & BIOMOLECULAR CHEMISTRY; v. 16, n. 35, p. 6450-6459, SEP 21 2018.
• Citações Web of Science: 6

Resumo

Antimicrobial and anti-proliferative meleagrin and oxaline are roquefortine C-derived alkaloids produced by fungi of the genus Penicillium. Tandem O-methylations complete the biosynthesis of oxaline from glandicoline B through meleagrin. Currently, little is known about the role of these methylation patterns in the bioactivity profile of meleagrin and oxaline. To establish the structural and mechanistic basis of methylation in these pathways, crystal structures were determined for two late-stage methyltransferases in the oxaline and meleagrin gene clusters from Penicillium oxalicum and Penicillium chrysogenum. The homologous enzymes OxaG and RoqN were shown to catalyze penultimate hydroxylamine O-methylation to generate meleagrin in vitro. Crystal structures of these enzymes in the presence of methyl donor S-adenosylmethionine revealed an open active site, which lacks an apparent base indicating that catalysis is driven by proximity effects. OxaC was shown to methylate meleagrin to form oxaline in vitro, the terminal pathway product. Crystal structures of OxaC in a pseudo-Michaelis complex containing sinefungin and meleagrin, and in a product complex containing S-adenosyl-homocysteine and oxaline, reveal key active site residues with His313 serving as a base that is activated by Glu369. These data provide structural insights into the enzymatic methylation of these alkaloids that include a rare hydroxylamine oxygen acceptor, and can be used to guide future efforts towards selective derivatization and structural diversification and establishing the role of methylation in bioactivity. (AU)

• Processo FAPESP: 13/50228-8 - Componentes da biodiversidade, e seus caracteres metabólicos, de ilhas do Brasil - uma abordagem integrada
• Beneficiário: Roberto Gomes de Souza Berlinck
• Linha de fomento: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 14/05670-7 - Proposta de projeto de sabático no grupo de pesquisas do professor David H. Sherman
• Beneficiário: Roberto Gomes de Souza Berlinck
• Linha de fomento: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 12/50026-3 - International collaboration in the chemistry of alkaloid natural product biosynthesis
• Beneficiário: Roberto Gomes de Souza Berlinck
• Linha de fomento: Auxílio à Pesquisa - Regular