1MEP

Crystal Structure of Streptavidin Double Mutant S45A/D128A with Biotin: Cooperative Hydrogen-Bond Interactions in the Streptavidin-Biotin System.

1MEP の概要

• エントリーDOI: 10.2210/pdb1mep/pdb
• 関連するPDBエントリー: 1MK5 1SWE
• 分子名称: Streptavidin, BIOTIN (3 entities in total)
• 機能のキーワード: homotetramer, biotin-binding protein
• 由来する生物種: Streptomyces avidinii
• 細胞内の位置: Secreted: P22629
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 53862.55

構造登録者

Hyre, D.E.,Le Trong, I.,Merritt, E.A.,Stenkamp, R.E.,Green, N.M.,Stayton, P.S. (登録日: 2002-08-08, 公開日: 2003-09-02, 最終更新日: 2024-02-14)

主引用文献

Hyre, D.E.,Le Trong, I.,Merritt, E.A.,Eccleston, J.F.,Green, N.M.,Stenkamp, R.E.,Stayton, P.S.
Cooperative hydrogen bond interactions in the streptavidin-biotin system
Protein Sci., 15:459-467, 2006

PubMed Abstract: The thermodynamic and structural cooperativity between the Ser45- and D128-biotin hydrogen bonds was measured by calorimetric and X-ray crystallographic studies of the S45A/D128A double mutant of streptavidin. The double mutant exhibits a binding affinity approximately 2x10(7) times lower than that of wild-type streptavidin at 25 degrees C. The corresponding reduction in binding free energy (DeltaDeltaG) of 10.1 kcal/mol was nearly completely due to binding enthalpy losses at this temperature. The loss of binding affinity is 11-fold greater than that predicted by a linear combination of the single-mutant energetic perturbations (8.7 kcal/mol), indicating that these two mutations interact cooperatively. Crystallographic characterization of the double mutant and comparison with the two single mutant structures suggest that structural rearrangements at the S45 position, when the D128 carboxylate is removed, mask the true energetic contribution of the D128-biotin interaction. Taken together, the thermodynamic and structural analyses support the conclusion that the wild-type hydrogen bond between D128-OD and biotin-N2 is thermodynamically stronger than that between S45-OG and biotin-N1.

PubMed: 16452627
DOI: 10.1110/ps.051970306

実験手法

X-RAY DIFFRACTION (1.65 Å)