title: Structural insights on the new mechanism of trehalose synthesis by trehalose synthase TreT from Pyrococcus horikoshii.
abstract: Many microorganisms produce trehalose for stability and survival against various environmental stresses. Unlike the widely distributed trehalose-biosynthetic pathway, which utilizes uridine diphosphate glucose and glucose-6-phosphate, the newly identified enzyme trehalose glycosyltransferring synthase (TreT) from hyperthermophilic bacteria and archaea synthesizes an α,α-trehalose from nucleoside diphosphate glucose and glucose. In the present study, we determined the crystal structure of TreT from Pyrococcus horikoshii at 2.3 Å resolution to understand the detailed mechanism of this novel trehalose synthase. The conservation of essential residues in TreT and the high overall structural similarity of the N-terminal domain to that of trehalose phosphate synthase (TPS) imply that the catalytic reaction of TreT for trehalose synthesis would follow a similar mechanism to that of TPS. The acceptor binding site of TreT shows a wide and commodious groove and lacks the long flexible loop that plays a gating role in ligand binding in TPS. The observation of a wide space at the fissure between two domains and the relative shift of the N-domain in one of the crystal forms suggest that an interactive conformational change between two domains would occur, allowing a more compact architecture for catalysis. The structural analysis and biochemical data in this study provide a molecular basis for understanding the synthetic mechanism of trehalose, or the nucleotide sugar in reverse reaction of the TreT, in extremophiles that may have important industrial implications.
authors.affiliation: Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon 305-806, Republic of Korea. ejwoo@kribb.re.kr
authors.forename: Eui-Jeon
authors.initials: EJ
authors.lastname: Woo
authors.forename: Soo-In
authors.initials: SI
authors.lastname: Ryu
authors.forename: Hyung-Nam
authors.initials: HN
authors.lastname: Song
authors.forename: Tae-Yang
authors.initials: TY
authors.lastname: Jung
authors.forename: Sei-Mee
authors.initials: SM
authors.lastname: Yeon
authors.forename: Hyun-Ah
authors.initials: HA
authors.lastname: Lee
authors.forename: Byoung Chul
authors.initials: BC
authors.lastname: Park
authors.forename: Kwan-Hwa
authors.initials: KH
authors.lastname: Park
authors.forename: Soo-Bok
authors.initials: SB
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D019281:Dimerization; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D043902:Pyrococcus horikoshii / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014199:Trehalose / Q000096:biosynthesis*
chemical_list: D050505:Mutant Proteins; D011994:Recombinant Proteins; D014199:Trehalose; D005964:Glucosyltransferases; C099692:trehalose synthase