Photolabeling evidence for calcium-induced conformational changes at the ATP binding site of scallop myosin.
Photolabeling evidence for calcium-induced conformational changes at the ATP binding site of scallop myosin.
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钙诱导扇贝肌球蛋白 ATP 结合位点构象变化的光标记证据。
DOI：
10.1073/pnas.90.1.35
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发表时间：
1993
影响因子：
11.1
通讯作者：
Yount,RG
中科院分区：
文献类型：
--
作者：
Kerwin,BA;Yount,RG
用ADP光亲和类似物2-[(4-叠氮-2-硝基苯基)氨基]乙基二磷酸(NANDP)鉴定了扇贝肌球蛋白活性部位在钙离子调节量影响下的构象变化。NANDP被Mn2+和钒酸盐捕获在活性中心，在没有添加镁和钙的情况下，优先光标记重链的Arg-128[Kerwin，B.&Young，R.(1992)BioCondiate Chem]。3,328-336]。然而，添加2 mM的镁离子和调节量的钙离子(0.01-1微米)使重链的主要标记转移到重链的Cys-198上，这是一种钙依赖的方式。当去除调节轻链或在类似条件下检查非调节头部(亚片段1)时，光标记图案中的这种钙依赖的变化是不存在的。这些结果表明，Arg-128和Cys-198都是嘌呤结合位点的一部分，该结合位点随着钙离子与调控结构域的结合而发生构象变化。
A change in the conformation of the active site of scallop myosin under the influence of regulatory amounts of Ca2+ has been identified by use of the ADP photoaffinity analog 2-[(4-azido-2-nitrophenyl)amino]ethyl diphosphate (NANDP). NANDP, trapped at the active site with Mn2+ and vanadate, photolabeled preferentially Arg-128 of the heavy chain in the absence of added Mg2+ and Ca2+ [Kerwin, B. & Yount, R. (1992) Bioconjugate Chem. 3, 328-336]. However, addition of 2 mM Mg2+ and regulatory amounts of Ca2+ (0.01-1 microM) shifted the predominant labeling to Cys-198 of the heavy chain in a Ca(2+)-dependent manner. This Ca(2+)-dependent change in the photolabeling pattern was absent when the regulatory light chains were removed or when the unregulated head (subfragment 1) was examined under similar conditions. These results demonstrate that both Arg-128 and Cys-198 are part of the purine binding site which undergoes a conformational change in response to Ca2+ binding to the regulatory domain.