title: Crystallographic studies of the complexes of antiviral protein griffithsin with glucose and N-acetylglucosamine.
abstract: Crystal structures of complexes of an antiviral lectin griffithsin (GRFT) with glucose and N-acetylglucosamine were solved and refined at high resolution. In both complexes, all six monosaccharide-binding sites of GRFT were occupied and the mode of binding was similar to that of mannose. In our previous attempts to obtain a complex with N-acetylglucosamine by soaking, only a single site was occupied; thus, cocrystallization was clearly superior despite lower concentration of the ligand. Isothermal titration calorimetric experiments with N-acetylglucosamine, glucose, and mannose provided enthalpic evidence of distinct binding differences between the three monosaccharides. A comparison of the mode of binding of different monosaccharides is discussed in the context of the antiviral activity of GRFT, based on specific binding to high-mannose-containing complex carbohydrates found on viral envelopes.
authors.affiliation: Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, NCI-Frederick, MD 21702-1201, USA.
authors.forename: Natasza E
authors.initials: NE
authors.lastname: Ziółkowska
authors.forename: Shilpa R
authors.initials: SR
authors.lastname: Shenoy
authors.forename: Barry R
authors.initials: BR
authors.lastname: O'Keefe
authors.forename: Alexander
authors.initials: A
authors.lastname: Wlodawer
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry* / Q000378:metabolism; D000998:Antiviral Agents / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray / Q000379:methods*; D005947:Glucose / Q000737:chemistry* / Q000378:metabolism; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism; D008358:Mannose / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D017433:Protein Structure, Secondary
chemical_list: D000998:Antiviral Agents; D037102:Lectins; D005947:Glucose; D008358:Mannose; D000117:Acetylglucosamine