High- and low-abundance chemoreceptors in Escherichia coli: Differential activities associated with closely related cytoplasmic domains
High- and low-abundance chemoreceptors in Escherichia coli: Differential activities associated with closely related cytoplasmic domains
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DOI：
10.1128/jb.179.21.6714-6720.1997
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发表时间：
1997-11-01
影响因子：
3.2
通讯作者：
Hazelbauer, GL
中科院分区：
文献类型：
--
作者：
Feng, XH;Baumgartner, JW;Hazelbauer, GL
在大肠杆菌中，两个高丰度的化学受体存在于细胞剂量中，大约是两个低丰度受体的十倍，在没有高丰度受体的情况下，细胞表现出异常低的翻滚频率，其余受体在空间梯度中介导定向迁移的能力受到很大影响。我们发现，在一定剂量范围内增加低丰度受体Trg的细胞量并不能缓解这些缺陷，因此得出结论，高丰度受体和低丰度受体不仅仅是因为它们在野生型细胞中的不同剂量，而且还因为它们固有的活性差异。通过建立低丰度受体Trg和高丰度受体TSR的杂交，我们研究了这种固有差异可以定位到特定受体结构域的可能性，发现高丰度受体TSR的细胞质结构域赋予了低丰度受体Trg该受体类的基本特征，尽管正是在这个结构域中，HCO受体之间的残基同一性基本上是保守的。
In Escherichia coli, two high-abundance chemoreceptors are present in cellular dosages approximately tenfold greater than two low-abundance receptors, In the absence of high-abundance receptors, cells exhibit an abnormally low tumble frequency and the ability of the remaining receptors to mediate directed migration in spatial gradients is substantially compromised. We found that increasing the cellular amount of the low-abundance receptor Trg over a range of dosages did not alleviate these defects and thus concluded that high- and low-abundance receptors are distinguished not simply by their different dosages in a wild-type cell but also by an inherent difference in activity. By creating hybrids of the low-abundance receptor Trg and the high-abundance receptor Tsr, we investigated the possibility that this inherent difference could be localized to a specific receptor domain and found that the cytoplasmic domain of the high-abundance receptor Tsr conferred the essential features of that receptor class on the low-abundance receptor Trg, even though it is in this domain that residue identity between the hco receptors is substantially conserved.