Structural insights on the new mechanism of trehalose synthesis by trehalose synthase TreT from Pyrococcus horikoshii.
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.
Woo
Eui-Jeon
EJ
Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon 305-806, Republic of Korea. ejwoo@kribb.re.kr
Ryu
Soo-In
SI
Song
Hyung-Nam
HN
Jung
Tae-Yang
TY
Yeon
Sei-Mee
SM
Lee
Hyun-Ah
HA
Park
Byoung Chul
BC
Park
Kwan-Hwa
KH
Lee
Soo-Bok
SB
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*
D050505:Mutant Proteins; D011994:Recombinant Proteins; D014199:Trehalose; D005964:Glucosyltransferases; C099692:trehalose synthase