論文

基本情報

氏名 古賀 雄一
氏名(カナ) コガ ユウイチ
氏名(英語) Koga Yuuichi
所属 工学部 応用化学科
職名 教授
researchmap研究者コード 5000076449
researchmap機関 岡山理科大学

題名

A hyperthermophilic protein acquires function at the cost of stability

単著・共著の別

 

著者

Atsushi Mukaiyama
Mitsuru Haruki
Motonori Ota
Yuichi Koga
Kazufumi Takano
Shigenori Kanaya

概要

Active-site residues are not often optimized for conformational stability (activity-stability trade-offs) in proteins from organisms that grow at moderate temperature. It is unknown if the activity-stability trade-offs can be applied to proteins from hyperthermophiles. Because enzymatic activity usually increases at higher temperature and hyperthermophilic proteins need high conformational stability, they might not sacrifice the stability for their activity. This study attempts to clarify the contribution of active-site residues to the conformational stability of a hyperthermophilic protein. We therefore examined the thermodynamic stability and enzymatic activity of wild-type and active-site mutant proteins (D7N, E8A, E8Q, D105A, and D135A) of ribonuclease HII from Thermococcus kodakaraensis (Tk-RNase HII). Guanidine hydrochloride (GdnHCl)-induced denaturation was measured with circular dichroism at 220 nm, and heat-induced denaturation was studied with differential scanning calorimetry. Both GdnHCl- and heat-induced denaturation were highly reversible in these proteins. All the mutations of these active-site residues, except that of Glu8 to Gln, reduced the enzymatic activity dramatically but increased the protein stability by 7.0 to 11.1 kJ mol(-1) at 50 degrees C. The mutation of Glu8 to Gln did not seriously affect the enzymatic activity and increased the stability only by 2.5 kJ mol(-1) at 50 degrees C. These results indicate that hyperthermophilic proteins also exhibit the activity-stability trade-offs. Therefore, the architectural mechanism for hyperthermophilic proteins is equivalent to that for proteins at normal temperature.

発表雑誌等の名称

BIOCHEMISTRY

出版者

AMER CHEMICAL SOC

45

42

開始ページ

12673

終了ページ

12679

発行又は発表の年月

2006-10

査読の有無

有り

招待の有無

無し

記述言語

英語

掲載種別

研究論文(学術雑誌)

ISSN

 

ID:DOI

10.1021/bi060907v

ID:NAID(CiNiiのID)

 

ID:PMID

 

JGlobalID

 

arXiv ID

 

ORCIDのPut Code

 

DBLP ID