5CHA

THE REFINEMENT AND THE STRUCTURE OF THE DIMER OF ALPHA-*CHYMOTRYPSIN AT 1.67-*ANGSTROMS RESOLUTION

「3CHA」から置き換えられました

5CHA の概要

• エントリーDOI: 10.2210/pdb5cha/pdb
• 分子名称: ALPHA-CHYMOTRYPSIN A, ... (4 entities in total)
• 機能のキーワード: hydrolase (serine proteinase)
• 由来する生物種: Bos taurus (cattle); 詳細
• 細胞内の位置: Secreted, extracellular space: P00766 P00766 P00766
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 50525.12

構造登録者

Blevins, R.A.,Tulinsky, A. (登録日: 1985-01-22, 公開日: 1985-04-01, 最終更新日: 2024-10-16)

主引用文献

Blevins, R.A.,Tulinsky, A.
The refinement and the structure of the dimer of alpha-chymotrypsin at 1.67-A resolution.
J.Biol.Chem., 260:4264-4275, 1985

PubMed Abstract: The two molecules of the asymmetric unit of the pH 3.5 conformer of alpha-chymotrypsin have been refined at 1.67-A resolution using restrained least squares methods with Hendrickson's program (PROLSQ). The final R factor is 0.179 (including 247 water molecules). The folding of the main chain of the independent molecules is the same within experimental error but the same does not generally apply to the side chain stereochemistry. From this we conclude that the folding of a protein structure is basically independent of most of the detailed stereochemistry of its side chains. The side chains of the interface region between the independent molecules display pronounced asymmetry. This asymmetry suggests that dynamic and asymmetrical structural changes take place at the time of oligomerization leading to more energetically favorable interactions for the dimer. Comparison of the structures of the independent molecules of alpha-chymotrypsin with the structure of monomeric gamma-chymotrypsin revealed that although the folding of the three molecules is essentially the same, numerous and significant differences pervade the side chain stereochemistry attributable to general flexibility. The specificity site of alpha-chymotrypsin is occupied by ordered water molecules in a similar way to gamma-chymotrypsin and other proteins. Some of these water molecules are displaced when substrate binds to the enzyme, while the others appear to help identify and position the aromatic side chain in catalysis.

PubMed: 3980476

実験手法

X-RAY DIFFRACTION (1.67 Å)