1FEV

CRYSTAL STRUCTURE OF THE ALA4AIB MUTATION IN RNASE S

1FEV の概要

• エントリーDOI: 10.2210/pdb1fev/pdb
• 関連するPDBエントリー: 1D5D 1D5E 1D5H 1RBH 1RNV
• 分子名称: S PEPTIDE, S PROTEIN, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: alpha aminoisobutyric acid, aib, hydrolase
• 由来する生物種: Bos taurus (cattle); 詳細
• 細胞内の位置: Secreted: P61823 P61823
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 13139.75

構造登録者

Ratnaparkhi, G.S.,Varadarajan, R. (登録日: 2000-07-23, 公開日: 2000-08-09, 最終更新日: 2021-11-03)

主引用文献

Ratnaparkhi, G.S.,Awasthi, S.K.,Rani, P.,Balaram, P.,Varadarajan, R.
Structural and thermodynamic consequences of introducing alpha-aminoisobutyric acid in the S peptide of ribonuclease S.
Protein Eng., 13:697-702, 2000

PubMed Abstract: The S protein-S peptide interaction is a model system to study binding thermodynamics in proteins. We substituted alanine at position 4 in S peptide by alpha-aminoisobutyric acid (Aib) to investigate the effect of this substitution on the conformation of free S peptide and on its binding to S protein. The thermodynamic consequences of this replacement were studied using isothermal titration calorimetry. The structures of the free and complexed peptides were studied using circular dichroic spectroscopy and X-ray crystallography, respectively. The alanine4Aib replacement stabilizes the free S peptide helix and does not perturb the tertiary structure of RNase S. Surprisingly, and in contrast to the wild-type S peptide, the DeltaG degrees of binding of peptide to S pro, over the temperature range 5-30 degrees C, is virtually independent of temperature. At 25 degrees C, the DeltaDeltaG degrees, DeltaDeltaH degrees, DeltaDeltaS and DeltaDeltaCp of binding are 0.7 kcal/mol, 2.8 kcal/mol, 6 kcal/mol x K and -60 kcal/mol x K, respectively. The positive value of DeltaDeltaS is probably due to a decrease in the entropy of uncomplexed alanine4Aib relative to the wild-type peptide. The positive value of DeltaDeltaH: degrees is unexpected and is probably due to favorable interactions formed in uncomplexed alanine4Aib. This study addresses the thermodynamic and structural consequences of a replacement of alanine by Aib both in the unfolded and complexed states in proteins.

PubMed: 11112508
DOI: 10.1093/protein/13.10.697

実験手法

X-RAY DIFFRACTION (2.25 Å)