Functional Design of Bacterial Mechanosensitive Channels
Functional Design of Bacterial Mechanosensitive Channels
复制标题
细菌机械敏感通道的功能设计
DOI：
--
复制
发表时间：
2002
影响因子：
4.8
通讯作者：
P. Blount
中科院分区：
文献类型：
--
作者：
K. Okada;P. Moe;P. Blount
MScS 和 MScL 是细菌质膜中发现的机械敏感通道，它们响应膜张力而打开大孔。这些通道的作用是缓解快速渗透压休克引起的细胞过度膨胀。尽管人们对MscL的结构和分子机制了解很多，但与MscS活性相关的基因直到最近才被鉴定出来。此前，已表明消除大肠杆菌yggB的表达会消除MscS活性的主要部分。 YggB 与 MscL 的不同之处在于没有明显的结构相似性。在这里，我们在蛋白脂质体中重建了纯化的YggB，并成功检测了MscS通道活性，证实纯化的YggB蛋白编码MscS活性。此外，为了定义通道蛋白的功能区域，我们对结构基因进行了随机诱变，并分离了引起功能获得表型的突变体。生理实验表明，突变的通道允许溶质从细胞中泄漏，这表明通道打开不当。有趣的是，这种突变在位置和特征上与 MscL 中产生相似表型的突变相似。因此，尽管MscS和MscL机械敏感通道在结构上截然不同，但它们的门控机制可能有相似之处。
MscS and MscL are mechanosensitive channels found in bacterial plasma membranes that open large pores in response to membrane tension. These channels function to alleviate excess cell turgor invoked by rapid osmotic downshock. Although much is known of the structure and molecular mechanisms underlying MscL, genes correlating with MscS activity have only recently been identified. Previously, it was shown that eliminating the expression ofEscherichia coli yggB removed a major portion of MscS activity. YggB is distinct from MscL by having no obvious structural similarity. Here we have reconstituted purified YggB in proteoliposomes and have successfully detected MscS channel activity, confirming that purified YggB protein encodes MscS activity. Additionally, to define functional regions of the channel protein, we have randomly mutagenized the structural gene and isolated a mutant that evokes a gain-of-function phenotype. Physiological experiments demonstrate that the mutated channel allows leakage of solutes from the cell, suggesting inappropriate channel opening. Interestingly, this mutation is analogous in position and character to mutations yielding a similar phenotype in MscL. Hence, although MscS and MscL mechanosensitive channels are structurally quite distinct, there may be analogies in their gating mechanisms.
登录
查看更多内容
影响因子：
3.4
作者：
SUKHAREV, SI;MARTINAC, B;KUNG, C
通讯作者：
KUNG, C
影响因子：
18.2
作者：
S. Sukharev;P. Blount;B. Martinac;C. Kung
通讯作者：
S. Sukharev;P. Blount;B. Martinac;C. Kung
影响因子：
11.4
作者：
Blount, P;Sukharev, SI;Kung, C
通讯作者：
Kung, C
DOI：
10.1073/pnas.95.19.11471
发表时间：
1998-09-15
影响因子：
11.1
作者：
Ou, XR;Blount, P;Kung, C
通讯作者：
Kung, C
影响因子：
3.4
作者：
Yoshimura, K;Batiza, A;Kung, C
通讯作者：
Kung, C