title: Structure of the ent-Copalyl Diphosphate Synthase PtmT2 from Streptomyces platensis CB00739, a Bacterial Type II Diterpene Synthase.
abstract: Terpenoids are the largest and most structurally diverse family of natural products found in nature, yet their presence in bacteria is underappreciated. The carbon skeletons of terpenoids are generated through carbocation-dependent cyclization cascades catalyzed by terpene synthases (TSs). Type I and type II TSs initiate cyclization via diphosphate ionization and protonation, respectively, and protein structures of both types are known. Most plant diterpene synthases (DTSs) possess three α-helical domains (αβγ), which are thought to have arisen from the fusion of discrete, ancestral bacterial type I TSs (α) and type II TSs (βγ). Type II DTSs of bacterial origin, of which there are no structurally characterized members, are a missing piece in the structural evolution of TSs. Here, we report the first crystal structure of a type II DTS from bacteria. PtmT2 from Streptomyces platensis CB00739 was verified as an ent-copalyl diphosphate synthase involved in the biosynthesis of platensimycin and platencin. The crystal structure of PtmT2 was solved at a resolution of 1.80 Å, and docking studies suggest the catalytically active conformation of geranylgeranyl diphosphate (GGPP). Site-directed mutagenesis confirmed residues involved in binding the diphosphate moiety of GGPP and identified DxxxxE as a potential Mg(2+)-binding motif for type II DTSs of bacterial origin. Finally, both the shape and physicochemical properties of the active sites are responsible for determining specific catalytic outcomes of TSs. The structure of PtmT2 fundamentally advances the knowledge of bacterial TSs, their mechanisms, and their role in the evolution of TSs.
authors.affiliation: Department of Chemistry, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Rudolf
authors.affiliation: Department of Chemistry, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Liao-Bin
authors.initials: LB
authors.lastname: Dong
authors.affiliation: Department of Biosciences, Rice University , Houston, Texas 77005, United States.
authors.forename: Hongnan
authors.initials: H
authors.lastname: Cao
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Catherine
authors.initials: C
authors.lastname: Hatzos-Skintges
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Osipiuk
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Endres
authors.affiliation: Department of Chemistry, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Chin-Yuan
authors.initials: CY
authors.lastname: Chang
authors.affiliation: Department of Chemistry, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Ming
authors.initials: M
authors.lastname: Ma
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Babnigg
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
authors.affiliation: Department of Biosciences, Rice University , Houston, Texas 77005, United States.
authors.forename: George N
authors.initials: GN
authors.lastname: Phillips
authors.affiliation: Department of Chemistry, The Scripps Research Institute , Jupiter, Florida 33458, United States.|Department of Molecular Therapeutics, The Scripps Research Institute , Jupiter, Florida 33458, United States.|Natural Products Library Initiative, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Ben
authors.initials: B
authors.lastname: Shen
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D008958:Models, Molecular; D010755:Organophosphates / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology*
chemical_list: D010755:Organophosphates; C408747:copalyl diphosphate; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase