2X6W

Tailspike protein mutant E372Q of E.coli bacteriophage HK620 in complex with hexasaccharide

2X6W の概要

• エントリーDOI: 10.2210/pdb2x6w/pdb
• 関連するPDBエントリー: 2VJI 2VJJ 2X6X 2X6Y 2X85
• 分子名称: TAIL SPIKE PROTEIN, alpha-D-glucopyranose-(1-6)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-3)-[alpha-L-rhamnopyranose-(1-6)-alpha-D-glucopyranose-(1-4)][2-acetamido-2-deoxy-beta-D-glucopyranose-(1-3)]alpha-D-galactopyranose-(1-3)-2-acetamido-2-deoxy-alpha-D-glucopyranose, SODIUM ION, ... (5 entities in total)
• 機能のキーワード: viral protein, beta-helix, hydrolase
• 由来する生物種: ENTEROBACTERIA PHAGE HK620
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 66155.64

構造登録者

Lorenzen, N.K.,Mueller, J.J.,Heinemann, U.,Seckler, R.,Barbirz, S. (登録日: 2010-02-22, 公開日: 2011-03-02, 最終更新日: 2023-12-20)

主引用文献

Broeker, N.K.,Gohlke, U.,Muller, J.J.,Uetrecht, C.,Heinemann, U.,Seckler, R.,Barbirz, S.
Single Amino Acid Exchange in Bacteriophage Hk620 Tailspike Protein Results in Thousand-Fold Increase of its Oligosaccharide Affinity.
Glycobiology, 23:59-, 2013

PubMed Abstract: Bacteriophage HK620 recognizes and cleaves the O-antigen polysaccharide of Escherichia coli serogroup O18A1 with its tailspike protein (TSP). HK620TSP binds hexasaccharide fragments with low affinity, but single amino acid exchanges generated a set of high-affinity mutants with submicromolar dissociation constants. Isothermal titration calorimetry showed that only small amounts of heat were released upon complex formation via a large number of direct and solvent-mediated hydrogen bonds between carbohydrate and protein. At room temperature, association was both enthalpy- and entropy-driven emphasizing major solvent rearrangements upon complex formation. Crystal structure analysis showed identical protein and sugar conformers in the TSP complexes regardless of their hexasaccharide affinity. Only in one case, a TSP mutant bound a different hexasaccharide conformer. The extended sugar binding site could be dissected in two regions: first, a hydrophobic pocket at the reducing end with minor affinity contributions. Access to this site could be blocked by a single aspartate to asparagine exchange without major loss in hexasaccharide affinity. Second, a region where the specific exchange of glutamate for glutamine created a site for an additional water molecule. Side-chain rearrangements upon sugar binding led to desolvation and additional hydrogen bonding which define this region of the binding site as the high-affinity scaffold.

PubMed: 22923442
DOI: 10.1093/GLYCOB/CWS126

実験手法

X-RAY DIFFRACTION (1.35 Å)