5JB5

A simplified BPTI variant containing 22 alanines out of 58 residues

5JB5 の概要

• エントリーDOI: 10.2210/pdb5jb5/pdb
• 関連するPDBエントリー: 5JB4 5JB6 5JB7
• 分子名称: Pancreatic trypsin inhibitor, SULFATE ION (3 entities in total)
• 機能のキーワード: proteinase inhibitor, hydrolase inhibitor
• 由来する生物種: Bos taurus (Bovine)
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 17653.72

構造登録者

Islam, M.M. (登録日: 2016-04-13, 公開日: 2017-04-19, 最終更新日: 2024-10-23)

主引用文献

Islam, M.M.,Yohda, M.,Kidokoro, S.,Kuroda, Y.
Crystal structures of highly simplified BPTIs provide insights into hydration-driven increase of unfolding enthalpy
Sci Rep, 7:41205-41205, 2017

PubMed Abstract: We report a thermodynamic and structural analysis of six extensively simplified bovine pancreatic trypsin inhibitor (BPTI) variants containing 19-24 alanines out of 58 residues. Differential scanning calorimetry indicated a two-state thermal unfolding, typical of a native protein with densely packed interior. Surprisingly, increasing the number of alanines induced enthalpy stabilization, which was however over-compensated by entropy destabilization. X-ray crystallography indicated that the alanine substitutions caused the recruitment of novel water molecules facilitating the formation of protein-water hydrogen bonds and improving the hydration shells around the alanine's methyl groups, both of which presumably contributed to enthalpy stabilization. There was a strong correlation between the number of water molecules and the thermodynamic parameters. Overall, our results demonstrate that, in contrast to our initial expectation, a protein sequence in which over 40% of the residues are alanines can retain a densely packed structure and undergo thermal denaturation with a large enthalpy change, mainly contributed by hydration.

PubMed: 28266637
DOI: 10.1038/srep41205

実験手法

X-RAY DIFFRACTION (1.6 Å)