2Z1G

Crystal structure of E.coli RNase HI surface charged mutant(Q4R/T40E/Q72H/Q76K/Q80E/T92K/Q105K)

2Z1G の概要

• エントリーDOI: 10.2210/pdb2z1g/pdb
• 関連するPDBエントリー: 2Z1H 2Z1I 2Z1J
• 分子名称: Ribonuclease HI (2 entities in total)
• 機能のキーワード: rnase hi, thermostability, surface-charge residue, hydrolase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm (Potential): P0A7Y4
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 17721.26

構造登録者

You, D.J.,Fukuchi, S.,Nishikawa, K.,Koga, Y.,Takano, K.,Kanaya, S. (登録日: 2007-05-08, 公開日: 2007-11-13, 最終更新日: 2023-11-01)

主引用文献

You, D.-J.,Fukuchi, S.,Nishikawa, K.,Koga, Y.,Takano, K.,Kanaya, S.
Protein Thermostabilization Requires a Fine-tuned Placement of Surface-charged Residues
J.Biochem.(Tokyo), 142:507-516, 2007

PubMed Abstract: Using the information from the genome projects, recent comparative studies of thermostable proteins have revealed a certain trend of amino acid composition in which polar residues are scarce and charged residues are rich on the protein surface. To clarify experimentally the effect of the amino acid composition of surface residues on the thermostability of Escherichia coli Ribonuclease HI (RNase HI), we constructed six variants in which five to eleven polar residues were replaced by charged residues (5C, 7Ca, 7Cb, 9Ca, 9Cb and 11C). The thermal denaturation experiments indicated that all of the variant proteins are 3.2-10.1 degrees C in Tm less stable than the wild proteins. The crystal structures of resultant protein variants 7Ca, 7Cb, 9Ca and 11C closely resemble that of E. coli RNase HI in their global fold, and several different hydrogen bonding and ion-pair interactions are formed by the mutations. Comparison of the crystal structures of these variant proteins with that of E. coli RNase HI reveals that thermal destabilization is apparently related to electrostatic repulsion of the charged residues with neighbours. This result suggests that charged residues of natural thermostable proteins are strictly posted on the surface with optimal interactions and without repulsive interactions.

PubMed: 17761696
DOI: 10.1093/jb/mvm157

実験手法

X-RAY DIFFRACTION (2.1 Å)