Structure, function, and on-off switching of a core unit contact between CheA kinase and CheW adaptor protein in the bacterial chemosensory array: A disulfide mapping and mutagenesis study.
Structure, function, and on-off switching of a core unit contact between CheA kinase and CheW adaptor protein in the bacterial chemosensory array: A disulfide mapping and mutagenesis study.
复制标题
DOI：
10.1021/bi401159k
复制
发表时间：
2013-11-05
期刊：
影响因子：
2.9
通讯作者：
Falke, Joseph J.
中科院分区：
文献类型：
--
作者：
Natale, Andrew M.;Duplantis, Jane L.;Piasta, Kene N.;Falke, Joseph J.
大肠杆菌和鼠伤寒沙门氏菌的超灵敏、超稳定的化学感觉阵列是控制运动细菌和古细菌细胞趋化性的大型、保守的感觉阵列家族的代表。膜结合阵列的核心框架是由三个组成部分组成的晶格：跨膜受体、细胞质His激酶（CheA）和细胞质衔接蛋白（CheW）。该领域的结构研究已经揭示了阵列的整体结构和特定组件之间的复合物，但关于定义阵列结构和组件之间传输信号的基本蛋白质-蛋白质界面仍有待了解。这项研究的重点是在工作的膜结合阵列中激酶和接头蛋白之间的一个关键接触的结构、功能和开关。具体来说，该研究定位了假定的激酶-接头环中的界面1，其中激酶调节结构域的亚结构域1与接头蛋白的亚结构域2接触。两种独立的方法-二硫定位和定点Trp和Ala诱变-被用于(i)测试界面1的结构模型和（ii）研究其在稳定的激酶结合和受体调节的激酶开关中的功能作用。研究是在功能性、膜结合阵列或活细胞中进行的。研究结果表明，二元和三元配合物的晶体结构准确地描述了激酶激活状态下的天然界面。此外，研究结果表明，至少部分界面在其激酶抑制关闭状态下变得不那么紧密。总之，证据表明，该界面具有双重结构和信号功能，对于稳定的激酶结合到阵列中，对于阵列打开状态下的激酶激活，以及可能的吸引剂触发的激酶开关至关重要。本文提出了一个模型，描述了受体、激酶调节结构域和接头蛋白之间构象信号的协调传递。原则上，这个信号可以通过激酶适配器环传播到周围的阵列，采用一系列交替的冷冻动态转换，远距离传输低能引诱物信号。
The ultrasensitive, ultrastable bacterial chemosensory array of Escherichia coli and Salmonella typhimurium is representative of the large, conserved family of sensory arrays that control the cellular chemotaxis of motile bacteria and Archaea. The core framework of the membrane-bound array is a lattice assembled from three components: a transmembrane receptor, a cytoplasmic His kinase (CheA), and a cytoplasmic adaptor protein (CheW). Structural studies in the field have revealed the global architecture of the array and complexes between specific components, but much remains to be learned about the essential protein-protein interfaces that define array structure and transmit signals between components. This study has focused on the structure, function and on-off switching of a key contact between the kinase and adaptor proteins in the working, membrane-bound array. Specifically, the study addressed interface 1 in the putative kinase-adaptor ring where subdomain 1 of the kinase regulatory domain contacts subdomain 2 of the adaptor protein. Two independent approaches – disulfide mapping and site-directed Trp and Ala mutagenesis – were employed to (i) test the structural model of interface 1 and (ii) investigate its functional roles in both stable kinase incorporation and receptor-regulated kinase on-off switching. Studies were carried out in functional, membrane-bound arrays or in live cells. The findings reveal that crystal structures of binary and ternary complexes accurately depict the native interface in its kinase-activating on state. Furthermore, the findings indicate that at least part of the interface becomes less closely packed in its kinase-inhibiting off state. Together, the evidence shows the interface has a dual structural and signaling function that is crucial for stable kinase incorporation into the array, for kinase activation in the array on state, and likely for attractant-triggered kinase on-off switching. A model is presented that describes the concerted transmission of a conformational signal between the receptor, the kinase regulatory domain, and the adaptor protein. In principle, this signal could spread out into the surrounding array via the kinase-adaptor ring, employing a series of alternating frozen-dynamic transitions that transmit low-energy attractant signals long distances.
登录
查看更多内容
影响因子：
7.2
作者：
Balagopalan, Lakshmi;Coussens, Nathan P.;Sommers, Connie L.
通讯作者：
Sommers, Connie L.
影响因子：
10.5
作者：
Hazelbauer GL
通讯作者：
Hazelbauer GL
影响因子：
4.8
作者：
CHERVITZ, SA;FALKE, JJ
通讯作者：
FALKE, JJ
影响因子：
64.5
作者：
Bilwes, AM;Alex, LA;Simon, MI
通讯作者：
Simon, MI
影响因子：
6.8
作者：
Falke, JJ;Kim, SH
通讯作者：
Kim, SH