title: Diterpene cyclases and the nature of the isoprene fold.
abstract: The structures and mechanism of action of many terpene cyclases are known, but no structures of diterpene cyclases have yet been reported. Here, we propose structural models based on bioinformatics, site-directed mutagenesis, domain swapping, enzyme inhibition, and spectroscopy that help explain the nature of diterpene cyclase structure, function, and evolution. Bacterial diterpene cyclases contain approximately 20 alpha-helices and the same conserved "QW" and DxDD motifs as in triterpene cyclases, indicating the presence of a betagamma barrel structure. Plant diterpene cyclases have a similar catalytic motif and betagamma-domain structure together with a third, alpha-domain, forming an alphabetagamma structure, and in H(+)-initiated cyclases, there is an EDxxD-like Mg(2+)/diphosphate binding motif located in the gamma-domain. The results support a new view of terpene cyclase structure and function and suggest evolution from ancient (betagamma) bacterial triterpene cyclases to (betagamma) bacterial and thence to (alphabetagamma) plant diterpene cyclases.
authors.affiliation: Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Cao
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
authors.forename: Francis M
authors.initials: FM
authors.lastname: Mann
authors.forename: Cancan
authors.initials: C
authors.lastname: Huang
authors.forename: Dushyant
authors.initials: D
authors.lastname: Mukkamala
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hudock
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Mead
authors.forename: Sladjana
authors.initials: S
authors.lastname: Prisic
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Fu-Yang
authors.initials: FY
authors.lastname: Lin
authors.forename: Ting-Kai
authors.initials: TK
authors.lastname: Chang
authors.forename: Reuben J
authors.initials: RJ
authors.lastname: Peters
authors.forename: Eric
authors.initials: E
authors.lastname: Oldfield
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002070:Butadienes / Q000737:chemistry / Q000378:metabolism*; D016000:Cluster Analysis; D004224:Diterpenes / Q000378:metabolism*; D019143:Evolution, Molecular; D045782:Hemiterpenes / Q000737:chemistry / Q000378:metabolism*; D007535:Isomerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010420:Pentanes / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D002070:Butadienes; D004224:Diterpenes; D045782:Hemiterpenes; D010420:Pentanes; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C005059:isoprene; D019883:Alkyl and Aryl Transferases; D007535:Isomerases; C088741:abietadiene cyclase; D008274:Magnesium