Taxonomic group: fungi / Basidiomycota
(Phylum: Basidiomycota)
The structure was elucidated in this paperNCBI PubMed ID: 20078120Publication DOI: 10.1021/ja909129bJournal NLM ID: 7503056Publisher: American Chemical Society
Correspondence: Vasur J <jonas.vasur
gmail.com>; Ståhlberg J <jerry.stahlberg
molbio.slu.se>
Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden, Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden, Department of Biomaterials Sciences, Graduate School for Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, Molecular Structural Analysis, German Cancer Research Center, Heidelberg, Germany
Glycosynthases are precise molecular instruments for making specifically linked oligosaccharides. X-ray crystallography screening of ligands bound to the 1,3(4)-β-D-glucanase nucleophile mutant E115S of Phanerochaete chrysosporium Laminarinase 16A (Lam16A) showed that laminariheptaose (L7) bound in an arch with the reducing and nonreducing ends occupying either side of the catalytic cleft of the enzyme. The X-ray structure of Lam16A E115S in complex with R-laminariheptaosyl fluoride (αL7F) revealed how αL7F could make a nucleophilic attack upon itself. Indeed, when Lam16A E115S was allowed to react with αL7F the major product was a cyclic β-1,3-heptaglucan, as shown by mass spectrometry. NMR confirmed uniquely β-1,3-linkages and no reducing end. Molecular dynamics simulations indicate that the cyclic laminariheptaose molecule is not completely planar and that torsion angles at the glycosidic linkages fluctuate between two energy minima. This is the first report of a glycosynthase that joins the reducing and nonreducing ends of a single oligosaccharide and the first reported synthesis of cyclic β-glucan.
synthesis, cyclic glucan, laminarinase, Phanerochaete chrysosporium
Structure type: cyclic polymer repeating unit ; n=7
Location inside paper: Scheme 1, cL7
Trivial name: cyclic laminariheptaose
Compound class: glucan
Contained glycoepitopes: IEDB_1397514,IEDB_142488,IEDB_146664,IEDB_153543,IEDB_158555,IEDB_161166,IEDB_2278476,IEDB_2278477,IEDB_558869,IEDB_857743,IEDB_983931,SB_192
Methods: 13C NMR, 1H NMR, SDS-PAGE, DNA techniques, MALDI-TOF, CC, HSQC, reverse-phase HPLC
Enzymes that release or process the structure: Lam16A
Synthetic data: enzymatic
3D data: conformation data
NCBI Taxonomy refs (TaxIDs): 5306Reference(s) to other database(s): GTC:G51056AN
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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