1U9R

Crystal Structure of Staphylococcal Nuclease mutant V66E/P117G/H124L/S128A at Room Temperature

1U9R の概要

• エントリーDOI: 10.2210/pdb1u9r/pdb
• 関連するPDBエントリー: 1EY8
• 分子名称: Thermonuclease (2 entities in total)
• 機能のキーワード: staphylococcal nuclease, nuclease, hyperstable variant, internal waters, hydrolase
• 由来する生物種: Staphylococcus aureus
• 細胞内の位置: Nuclease A: Secreted. Nuclease B: Membrane: P00644
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 16792.26

構造登録者

Denisov, V.P.,Schlessman, J.L.,Garcia-Moreno, B.E.,Halle, B. (登録日: 2004-08-10, 公開日: 2004-12-21, 最終更新日: 2024-04-03)

主引用文献

Denisov, V.P.,Schlessman, J.L.,Garcia-Moreno, B.E.,Halle, B.
Stabilization of internal charges in a protein: water penetration or conformational change?
Biophys.J., 87:3982-3994, 2004

PubMed Abstract: The ionizable amino acid side chains of proteins are usually located at the surface. However, in some proteins an ionizable group is embedded in an apolar internal region. Such buried ionizable groups destabilize the protein and may trigger conformational changes in response to pH variations. Because of the prohibitive energetic cost of transferring a charged group from water to an apolar medium, other stabilizing factors must be invoked, such as ionization-induced water penetration or structural changes. To examine the role of water penetration, we have measured the 17O and 2H magnetic relaxation dispersions (MRD) for the V66E and V66K mutants of staphylococcal nuclease, where glutamic acid and lysine residues are buried in predominantly apolar environments. At neutral pH, where these residues are uncharged, we find no evidence of buried water molecules near the mutation site. This contrasts with a previous cryogenic crystal structure of the V66E mutant, but is consistent with the room-temperature crystal structure reported here. MRD measurements at different pH values show that ionization of Glu-66 or Lys-66 is not accompanied by penetration of long-lived water molecules. On the other hand, the MRD data are consistent with a local conformational change in response to ionization of the internal residues.

PubMed: 15377517
DOI: 10.1529/biophysj.104.048454

実験手法

X-RAY DIFFRACTION (2.1 Å)