title: A branched N-linked glycan at atomic resolution in the 1.12 A structure of rhamnogalacturonan acetylesterase.
abstract: The crystal structure of the glycoprotein rhamnogalacturonan acetylesterase from Aspergillus aculeatus has been refined to a resolution of 1.12 A using synchrotron data collected at 263 K. Both of the two putative N-glycosylation sites at Asn104 and Asn182 are glycosylated and, owing to crystal contacts, the glycan structure at Asn182 is exceptionally well defined in the electron-density maps, showing the six-carbohydrate structure Manalpha1-6(Manalpha1-3)Manalpha1-6Manbeta1-4GlcNAcbeta1-4GlcNAcbeta-Asn182. Equivalent carbohydrate residues were restrained to have similar geometries, but were refined without target values. The refined bond lengths and angles were compared with the values obtained from small-molecule studies that form the basis for the dictionaries used for glycoprotein refinement.
authors.affiliation: Centre for Crystallographic Studies, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Mølgaard
authors.forename: Sine
authors.initials: S
authors.lastname: Larsen
mesh_terms: D000115:Acetylesterase / Q000737:chemistry*; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*
chemical_list: D011134:Polysaccharides; C096859:rhamnogalacturonan acetylesterase; D000115:Acetylesterase