Thermal stability and structural variations of survivin and its deletants in aqueous solution as revealed by spectroscopy.
Thermal stability and structural variations of survivin and its deletants in aqueous solution as revealed by spectroscopy.
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DOI：
10.1021/jp200060q
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发表时间：
2011-05
期刊：
影响因子：
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通讯作者：
Yang Gao;M. Zhang;Huafei Zhang;Xianghui Yu;W. Kong;Xiao Zha;Yuqing Wu
中科院分区：
文献类型：
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作者：
Yang Gao;M. Zhang;Huafei Zhang;Xianghui Yu;W. Kong;Xiao Zha;Yuqing Wu
存活素以同源二聚体构象存在，在生物体中作为细胞凋亡的抑制因子。之前，我们发现N-末端残基截短至Arg 18的缺失体失去了与Smac/DIABLO的结合能力，但没有失去同二聚体的结合力。为了建立功能与结构稳定性之间的关系，本文研究了SurF及其缺失体在缓冲液中的热去折叠。荧光结果表明，随着N-末端的去除，三级结构的热稳定性急剧下降，尤其是SurΔN18。然而，使用圆二色性（CD）光谱，我们观察到的主要展开的二级结构没有受到很大的影响与N-末端删除。通过傅里叶变换红外光谱（FT-IR）和二维相关分析（2D correlation analysis）进一步分析了主要转变过程中的结构信息，这些转变过程与几种β-组分和α-螺旋的构象变化以及随后的聚集体和无规卷曲的增加有关。此外，更多的聚集体被发现形成较长的N-末端缺失在主要的解折叠。
Survivin exists as a homodimeric conformation to act as a suppressor of apoptosis in organisms. Previously, we found that the deletants with truncations of N-terminal residues up to Arg18 lost the binding ability to Smac/DIABLO but not the binding force of homodimers. In order to establish the relationship between function and structural stability, thermal unfolding of SurF and its deletants in buffer have been studied in the present paper. The fluorescent results indicated that with the removal of the N-terminus, the thermal stability of the tertiary structure dropped vigorously, especially for SurΔN18. However, using circular dichroism (CD) spectroscopy, we observed that the main unfolding of the secondary structures was not affected very much with N-terminus deletion. Fourier transform infrared (FT-IR) spectroscopy and two-dimensional (2D) correlation analysis were further used to provide structural information that occurred in the main transitions, which were associated with conformational changes of several β-components and α-helix, followed by the gain of some aggregations and random coils at high temperature. In addition, more aggregates were found to form for the longer N-terminal deletants during the main unfolding.