3AA3

A52L E. coli RNase HI

3AA3 の概要

• エントリーDOI: 10.2210/pdb3aa3/pdb
• 関連するPDBエントリー: 3AA2 3AA4 3AA5
• 分子名称: Ribonuclease HI (2 entities in total)
• 機能のキーワード: stability, cavity, endonuclease, hydrolase, magnesium, metal-binding, nuclease
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm : P0A7Y4
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 17665.08

構造登録者

Takano, K. (登録日: 2009-11-11, 公開日: 2010-10-06, 最終更新日: 2024-03-13)

主引用文献

Tanaka, M.,Chon, H.,Angkawidjaja, C.,Koga, Y.,Takano, K.,Kanaya, S.
Protein core adaptability: crystal structures of the cavity-filling variants of Escherichia coli RNase HI
Protein Pept.Lett., 17:1163-1169, 2010

PubMed Abstract: It has generally been accepted that an increase in protein stability is proportional to the increase in hydrophobicity. When a cavity is created by large-to-small substitutions of amino acid residues in protein cores, protein stability decreases 5.3 kJ/mol per single methyl(ene) group removal. In contrast, many reported cavity-filling mutations either failed to increase stability or produced marginal increases in stability; even in successful cases, the increase in stability was much lower than expected from the cost of single methyl(ene) group removal in cavity-creating mutations. Previously it was found that some cavity-filling mutant proteins at Ala52 in E. coli RNase HI increased stability, but decreased activity and they did not increase the stability to the degree expected by the hydrophobic effect alone. The present study attempted to structurally analyze these variant proteins, and it was found that substitutions have little effect on the overall fold but cause conformational strains with the neighboring residues. The present results and literature on cavity-creating/-filling variants provide insight into protein architecture, indicating that natural protein cores are able to accommodate larger side-chain residue by substitution; in other words, excess-packing may not be chosen in natural selection.

PubMed: 20423323
DOI: 10.2174/092986610791760342

実験手法

X-RAY DIFFRACTION (2.2 Å)