Solving the phase problem for carbohydrate-binding proteins using selenium derivatives of their ligands: a case study involving the bacterial F17-G adhesin.

• 发表时间: Jun 2003
• 来源期刊: Acta Crystallogr D Biol Crystallogr
• DOI: 10.1107/s0907444903007170
• PMID: 12777763
• 文章类型: Journal Article
• 作者列表: Buts L,Loris R,De Genst E,Oscarson S,Lahmann M,Messens J,Brosens E,Wyns L,De Greve H,Bouckaert J

Mesh: Acetylglucosamine / chemistry; Adhesins, Bacterial; Carrier Proteins / chemistry metabolism; Crystallization; Escherichia coli Proteins / chemistry; Hydrogen Bonding; Indicators and Reagents; Ligands; Models, Molecular; Protein Binding; Receptors, Cell Surface; Selenium Compounds / chemistry

Abstract

The Escherichia coli adhesin F17-G is a carbohydrate-binding protein that allows the bacterium to attach to the intestinal epithelium of young ruminants. The structure of the 17 kDa lectin domain of F17-G was determined using the anomalous dispersion signal of a selenium-containing analogue of the monosaccharide ligand N-acetyl-d-glucosamine in which the anomeric oxygen was replaced by an Se atom. A three-wavelength MAD data set yielded good experimental phases to 2.6 A resolution. The structure was refined to 1.75 A resolution and was used to solve the structures of the ligand-free protein and the F17-G-N-acetyl-d-glucosamine complex. This selenium-carbohydrate phasing method could be of general use for determining the structures of carbohydrate-binding proteins.