ATP对α-晶状体蛋白分子伴侣功能及构象的影响  

Effect of ATP on molecular chaperone function and conformation of α-crystallin

作　　者：易姝[1] 李平华[1] 黄远帅[2] 

机构地区：[1]重庆医科大学附属第一医院眼科,400016 [2]重庆医科大学医学检验系临床生化教研室

出　　处：《眼科研究》2008年第2期84-87,共4页Chinese Ophthalmic Research

摘　　要：目的探讨α-晶状体蛋白分子伴侣功能的作用机制。方法将柠檬酸合酶(CS)、盐酸胍和不同浓度的α-晶状体蛋白及3mmol/L的ATP温育,分光光度计测定CS的活性。α-晶状体蛋白与ATP温育后用荧光分光光度计检测其荧光发射光谱。结果α-晶状体蛋白不能使变性的CS复性,但能抑制盐酸胍诱导的CS凝聚,保护CS的失活且呈浓度依赖性。ATP可使这些作用增强。ATP浓度增高可导致α-晶状体蛋白色氨酸荧光强度降低。结论ATP可增强α-晶状体蛋白的分子伴侣功能且能改变α-晶状体蛋白的分子构象。Objective α-crystallin is a molecular chaperone function which plays an important role in maintaining transparence of crystalline lens. Present study was to evaluate the reactive mechanism of α-crystallin molecular chaperone function. Methods Citrate synthase（CS） from pig heart was incubated with guanidine hydrochloride（GdnHCI） for 1 hour. 50,150 and 300 nmol/L α-crystallin from calf was added respectively, and the aggregation of CS,unfolding and renaturing of CS in 150,300,600 nmol/L of α-crystallin was detected by GdnHCI. The protection of α-crystallin against inactivation of CS by GdnHCI was measured spectrophotometrically. At the same time,the above experiments were repeated in the presence of 3 mmol/L ATP. The fluorescence emission spectra of α-crystallin was monitored at 316 nm 〈 h 〈 400 nm in the absence and presence of varying concentrations of ATP. Results The relative light scattering value at 6 minutes after incubation was 0.05,0. 039,0. 028, 0. 017 in 0,50,150 and 300 nmol/L α-crystallin group respectively with a significant difference among them（ F = 95.7 ,P 〈 0. 000 1 ） ,and existence of ATP enhanced the inhibiting effect of α-crystallin on CS aggregation,showing a statistically difference in comparison with ATP absence group（ F = 22. 02 ,P =0. 000 2）. The percentages of survival CS was significantly increased in 1 and 2μmmol/L of α-crystallin group, and ATP elevated the percentages of CS survival（ F = 246.4, P 〈 0. 000 1 ）. A statistically difference was seen between with ATP and without ATP group （ F = 15.64, P = 0. 001 9）. The activity of CS within 2 hours was 0 in above concentration groups of α-crystallin. The fluorescence intensity of α-crystallin in 0,1,3 and 5 mmol/L ATP groups was 100% ,90. 8% ,79.7% and 58.6% ,respectively with a evident difference. Conclusion α-crystallin behaves as a molecular chaperone by preventing the unfolding and aggregation of CS in an ATP-dependent manner and actively protecting CS against inactivation in a concentratio

关 键 词：Α-晶状体蛋白 分子伴侣 腺苷三磷酸 

分 类 号：R776[医药卫生—眼科]