Removal of disulfide from acid stress chaperone HdeA does not wholly eliminate structure or function at low pH.
Removal of disulfide from acid stress chaperone HdeA does not wholly eliminate structure or function at low pH.
复制标题
从酸胁迫伴侣HdeA中去除二硫并不能完全消除低pH下的结构或功能。
DOI：
10.1016/j.bbrep.2021.101064
复制
发表时间：
2021-09
影响因子：
2.7
通讯作者：
Crowhurst KA
中科院分区：
文献类型：
--
作者：
Aguirre-Cardenas MI;Geddes-Buehre DH;Crowhurst KA
HdeA是一种酸应激伴侣蛋白，在各种致病性革兰氏阴性细菌的周质中发挥作用。它的主要功能是防止细菌在摄入受污染的食物后进入胃的酸性环境时，其他周质蛋白不可逆转地聚集；因此，它的作用是帮助细菌存活足够长的时间，进入肠道并定居。HdeA的作用机制是不寻常的，因为这种螺旋同源二聚体在中性pH下折叠时不活跃，但在低pH下二聚体解离并部分解离后激活。以前对化学还原剂的研究表明，分子内的二硫键在低pH值下对于维持HdeA的残基结构是重要的，并可能负责将暴露的疏水残基定位在一起，以结合未折叠的客户蛋白。为了探讨其在HdeA结构和伴侣功能中的作用，我们对二硫键进行了保守的半胱氨酸到丝氨酸的突变。我们发现，尽管在没有二硫键的情况下，在pH 2的情况下，残基结构大大减少，但它并没有完全丢失；相反，在pH 6的情况下，突变体几乎完全是随机卷曲。聚集分析表明，突变的HdeA虽然作为伴侣不如野生型成功，但仍然保持着令人惊讶的功能水平。这些研究强调，对于在低pH下稳定残基结构的因素和二硫键的作用，我们仍然有很多需要了解的地方。
HdeA is an acid-stress chaperone that operates in the periplasm of various strains of pathogenic gram-negative bacteria. Its primary function is to prevent irreversible aggregation of other periplasmic proteins when the bacteria enter the acidic environment of the stomach after contaminated food is ingested; its role is therefore to help the bacteria survive long enough to enter and colonize the intestines. The mechanism of operation of HdeA is unusual in that this helical homodimer is inactive when folded at neutral pH but becomes activated at low pH after the dimer dissociates and partially unfolds. Studies with chemical reducing agents previously suggested that the intramolecular disulfide bond is important for maintaining residual structure in HdeA at low pH and may be responsible for positioning exposed hydrophobic residues together for the purpose of binding unfolded client proteins. In order to explore its role in HdeA structure and chaperone function we performed a conservative cysteine to serine mutation of the disulfide. We found that, although residual structure is greatly diminished at pH 2 without the disulfide, it is not completely lost; conversely, the mutant is almost completely random coil at pH 6. Aggregation assays showed that mutated HdeA, although less successful as a chaperone than wild type, still maintains a surprising level of function. These studies highlight that we still have much to learn about the factors that stabilize residual structure at low pH and the role of disulfide bonds.
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DOI：
10.1016/j.bbapap.2020.140576
发表时间：
2021-03
期刊：
Biochimica et biophysica acta. Proteins and proteomics
影响因子：
--
作者：
Widjaja MA;Gomez JS;Benson JM;Crowhurst KA
通讯作者：
Crowhurst KA
酸胁迫期间大肠杆菌周质伴侣 HdeA 与其天然底物之间相互作用的表征
影响因子：
2.9
作者：
Yu, Xing-Chi;Yang, Chengfeng;Jin, Changwen
通讯作者：
Jin, Changwen
影响因子：
3.6
作者：
Waterman, SR;Small, PLC
通讯作者：
Small, PLC
影响因子：
2.7
作者：
DELAGLIO, F;GRZESIEK, S;BAX, A
通讯作者：
BAX, A
影响因子：
5.6
作者：
Gajiwala, KS;Burley, SK
通讯作者：
Burley, SK