title: Involvement of Lipocalin-like CghA in Decalin-Forming Stereoselective Intramolecular [4+2] Cycloaddition.
abstract: Understanding enzymatic Diels-Alder (DA) reactions that can form complex natural product scaffolds is of considerable interest. Sch 210972 1, a potential anti-HIV fungal natural product, contains a decalin core that is proposed to form through a DA reaction. We identified the gene cluster responsible for the biosynthesis of 1 and heterologously reconstituted the biosynthetic pathway in Aspergillus nidulans to characterize the enzymes involved. Most notably, deletion of cghA resulted in a loss of stereoselective decalin core formation, yielding both an endo (1) and a diastereomeric exo adduct of the proposed DA reaction. Complementation with cghA restored the sole formation of 1. Density functional theory computation of the proposed DA reaction provided a plausible explanation of the observed pattern of product formation. Based on our study, we propose that lipocalin-like CghA is responsible for the stereoselective intramolecular [4+2] cycloaddition that forms the decalin core of 1.
authors.affiliation: Department of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Yagishita
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mino
authors.affiliation: National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Uchiyama
authors.affiliation: Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Box 951569, Los Angeles, CA, 90095, USA.
authors.forename: Ashay
authors.initials: A
authors.lastname: Patel
authors.affiliation: Department of Chemical and Biomolecular Engineering and, Department of Chemistry and Biochemistry, University of California, 420 Westwood Plaza, Los Angeles, CA, 90095, USA.
authors.forename: Yit-Heng
authors.initials: YH
authors.lastname: Chooi
authors.affiliation: National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Goda
authors.affiliation: Department of Chemical and Biomolecular Engineering and, Department of Chemistry and Biochemistry, University of California, 420 Westwood Plaza, Los Angeles, CA, 90095, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Noguchi
authors.affiliation: Department of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: School of Biosciences, The University of Nottingham Malaysia Campus, Jalan Broga, Selangor, 43500, Malaysia.
authors.forename: Kinya
authors.initials: K
authors.lastname: Hotta
authors.affiliation: Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Box 951569, Los Angeles, CA, 90095, USA.
authors.forename: Kendall N
authors.initials: KN
authors.lastname: Houk
authors.affiliation: Department of Chemical and Biomolecular Engineering and, Department of Chemistry and Biochemistry, University of California, 420 Westwood Plaza, Los Angeles, CA, 90095, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan. kenji55@u-shizuoka-ken.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics; D061565:Cycloaddition Reaction; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D054834:Lipocalins / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D009281:Naphthalenes / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D005656:Fungal Proteins; D054834:Lipocalins; D009281:Naphthalenes; C007229:decalin
keywords: cycloaddition; decalin; density functional calculations; fungal metabolite; tetramic acid