Coyle J E, Texter F L, Ashcroft A E, Masselos D, Robinson C V, Radford S E
School of Biochemistry and Molecular Biology, University of Leeds, UK.
Nat Struct Biol. 1999 Jul;6(7):683-90. doi: 10.1038/10735.
The chaperonin GroEL binds folding intermediates of four-disulfidehen lysozyme transiently within its central cavity. Using stopped flow fluorescence we show that GroEL binds early intermediates in folding and accelerates the slow kinetic phase that reflects the reversal of non-native interactions involving tryptophan residues and the formation of the native state. Pulsed hydrogen exchange monitored by electrospray ionization mass spectrometry demonstrates that GroEL does not alter the folding mechanism, nor are protected species unfolded by the chaperonin. The data suggest a mechanism for GroEL-assisted folding in which the reorganization of non-native tertiary interactions is facilitated but domain folding is unperturbed.
伴侣蛋白GroEL在其中心腔内短暂结合四二硫键溶菌酶的折叠中间体。我们利用停流荧光技术表明，GroEL在折叠过程中结合早期中间体，并加速反映涉及色氨酸残基的非天然相互作用逆转和天然态形成的慢动力学阶段。通过电喷雾电离质谱监测的脉冲氢交换表明，GroEL不会改变折叠机制，伴侣蛋白也不会使受保护的物种去折叠。这些数据提示了一种GroEL辅助折叠的机制，其中非天然三级相互作用的重组得到促进，但结构域折叠不受干扰。
