The D14 and R138 ion pair is involved in dimeric arginine kinase activity, structural stability and folding

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• 作者：Hong-Li Geng^a ; ¹ ; Mei-Ru Bian^a ; ¹ ; Yang Liu^a ; ¹ ; Jiang Cao^a ; Chong Chen^a ; Zhi-Yuan Wang^a ; Zhen-Yu Li^a ; Ling-Yu Zeng^a ; Xiao-Yun Wang^c ; ^{xyunwangsdau@163.com" class="auth_mail} ; Qing-Yun Wu^b ; ^{qywu82@163.com" class="auth_mail} ; Kai-Lin Xu^a ; ^{lihmd@163.com" class="auth_mail}
• 关键词：AK ; arginine kinase ; CK ; creatine kinase ; PK ; phosphogen kinase ; IPTG ; isopropyl-d-thiogalactopyranoside ; ANS ; 1-anilinonaphtalene-8-sulfonate ; SEC ; size exclusion chromatography ; CD ; circular dichroism ; GdnHCl ; guanidine hydrochloride ; MG ; molten globule intermediate ; SDS ; sodium dodecyl sulfate ; WT ; wild type ; [胃]MRW ; mean residue ellipticity ; Emax ; emission maximum wavelength of the intrinsic fluorescence
• 刊名：International Journal of Biological Macromolecules
• 出版年：May, 2014
• 年：2014
• 卷：66
• 期：Complete
• 页码：302-310
• 全文大小：2973 K

文摘

Arginine kinase (AK) is a key enzyme in cellular energy metabolism of invertebrates. There are two conserved amino acid residues D14 and R138 in dimeric AK which form inter-subunit hydrogen bond. In Stichopus japonicus AK, mutations in these residues caused pronounced loss of activity, conformational changes and distinct substrate synergism alteration. Mutations (R138G, R138A and D14G) abolished D14 and R138 interaction disrupted the structure or conformation of S. japonicus AK. These R138G, R138A and D14G mutations changed their native assembles of dimeric AK and caused them in a partially unfolded state. The partially unfolded state of these mutant AKs made them prone to aggregate under environmental stress. The D14E/R138K and R138K mutant AKs showed similar characteristics to those of WT AK for forming the interaction which could replacement roles of D14 and R138 interaction. These results suggested that D14 and R138 interaction is involved in AK's activity, substrate synergism and structural stability.