title: Identification of tenuazonic acid as a novel type of natural photosystem II inhibitor binding in Q(B)-site of Chlamydomonas reinhardtii.
abstract: Tenuazonic acid (TeA) is a natural phytotoxin produced by Alternaria alternata, the causal agent of brown leaf spot disease of Eupatorium adenophorum. Results from chlorophyll fluorescence revealed TeA can block electron flow from Q(A) to Q(B) at photosystem II acceptor side. Based on studies with D1-mutants of Chlamydomonas reinhardtii, the No. 256 amino acid plays a key role in TeA binding to the Q(B)-niche. The results of competitive replacement with [(14)C]atrazine combined with JIP-test and D1-mutant showed that TeA should be considered as a new type of photosystem II inhibitor because it has a different binding behavior within Q(B)-niche from other known photosystem II inhibitors. Bioassay of TeA and its analogues indicated 3-acyl-5-alkyltetramic and even tetramic acid compounds may represent a new structural framework for photosynthetic inhibitors.
authors: Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China.
authors: Shiguo
authors: S
authors: Chen
authors: Xiaoming
authors: X
authors: Xu
authors: Xinbin
authors: X
authors: Dai
authors: Chunlong
authors: C
authors: Yang
authors: Sheng
authors: S
authors: Qiang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001280:Atrazine / Q000737:chemistry; D016227:Benzoquinones / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000201:enzymology*; D004579:Electron Transport / Q000187:drug effects; D008969:Molecular Sequence Data; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D011487:Protein Conformation; D011760:Pyrrolidinones / Q000737:chemistry / Q000494:pharmacology; D013720:Tenuazonic Acid / Q000378:metabolism / Q000633:toxicity*; D020524:Thylakoids / Q000187:drug effects
chemical_list: D016227:Benzoquinones; D045332:Photosystem II Protein Complex; D011760:Pyrrolidinones; C004532:quinone; C009435:tetramic acid; D013720:Tenuazonic Acid; D001280:Atrazine; D010100:Oxygen