Objective

To study the effect of the mutation in conserved G412E in Cct7p subunit of CCT complex on its cellular fate.

Results

TriC/CCT is a dynamic multimeric protein that assists in protein folding in an energy-dependent manner. A point mutation in the ATP binding pocket in the equatorial domain of the Cct7p subunit delays the doubling time. The cell size was twice the wild type, and the formation of protein aggregates suggests disturbed folding of the proteins. Upon growing in stressful conditions of arsenous acid and cadmium chloride, the mutant was lethal in As³⁺ but grew well in Cd²⁺ with 10.5 µg cadmium uptake mg⁻¹ compared to the wild type. The increased expression of vacuole transporters YCF1 and BPT1 by ten-fold and two-fold in mutant indicates the metal transportation to the vacuole.

Conclusion

CCT complex was vulnerable to the mutation in G412E in the Cct7p subunit of protein folding molecular machinery. Interestingly, already stressed cells provided robustness against oxidative stress and cadmium sequestration in the vacuole.

中文翻译：

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伴侣蛋白点突变增强酿酒酵母对镉的耐受性

客观的

研究CCT复合物Cct7p亚基保守G412E突变对其细胞命运的影响。

结果

TriC/CCT 是一种动态多聚体蛋白，以能量依赖的方式帮助蛋白质折叠。Cct7p 亚基赤道域中 ATP 结合口袋中的点突变延迟了倍增时间。细胞大小是野生型的两倍，蛋白质聚集体的形成表明蛋白质折叠受到干扰。在亚砷酸和氯化镉的压力条件下生长时，突变体在 As ^{3+ 中}是致命的，但在 Cd ^{2+ 中}生长良好，与野生型相比，镉摄取量为 10.5 µg mg ^-1。液泡转运蛋白YCF1和BPT1在突变体中的表达增加了 10 倍和 2 倍，表明金属向液泡的转运。

结论

CCT 复合物易受蛋白质折叠分子机制的 Cct7p 亚基中 G412E 突变的影响。有趣的是，已经受到压力的细胞在液泡中提供了抵抗氧化应激和镉螯合的鲁棒性。