Covalent cross-linking of single fibers from rabbit psoas increases oscillatory power.
Covalent cross-linking of single fibers from rabbit psoas increases oscillatory power.
复制标题
兔腰肌单纤维的共价交联增加了振荡功率。
DOI：
10.1016/s0006-3495(90)82582-0
复制
发表时间：
1990
影响因子：
3.4
通讯作者：
Kawai,M
中科院分区：
文献类型：
--
作者：
Tawada,K;Kawai,M
从化学处理过的兔腰大肌中分离出单个纤维，在20℃条件下用乙二胺四乙酸(1-ethyl-3-[3-dimethyl-amino)proyl]-carbodiimide，EDC)对其进行处理。通过硬度测量，22分钟的处理导致肌球蛋白头部和细丝之间有18%的共价交联度。这种处理还导致粗丝主干中肌球蛋白分子的杆状部分之间的共价交联。这样制备的纤维是稳定的，不溶于离子强度高达1000 mm的溶液。对制备的材料进行正弦分析，并根据三个指数过程(A)、(B)和(C)分析所产生的复模数数据。在生理离子强度(200 Mm)的活化液中，交联纤维的振荡功(过程B)比未处理的纤维大得多；这种差异归因于EDC处理过程(A)的下降。因此，经EDC处理的制剂的奈奎斯特曲线显示出昆虫类型的反应。我们的结论是，在这些条件下，交联型和非交联型肌球蛋白头部都有助于产生振荡功率。交联型制剂在高离子强度(500-1,000 mm)溶液中也表现出振荡功，这表明交联型肌球蛋白头能够利用ATP产生功。我们的结论是，过程(A)与跨桥循环中的基本步骤无关，但可能与跨桥外的动力学有关，如细丝滑动或肌节重排。
Single fibers from chemically skinned rabbit psoas muscle were treated with 1-ethyl-3-[3-dimethyl-amino)proyl]-carbodiimide (EDC) at 20 degrees C after rigor was induced. A 22-min treatment resulted in 18% covalent cross-linking between myosin heads and the thin filament as determined by stiffness measurements. This treatment also results in covalent cross-linking among rod portions of myosin molecules in the backbone of the thick filament. The fibers thus prepared are stable and do not dissolve in solutions at ionic strengths as high as 1,000 mM. The preparation was subjected to sinusoidal analysis, and the resulting complex modulus data were analyzed in terms of three exponential processes, (A), (B), and (C). Oscillatory work (process B) was much greater in the cross-linked fibers than in untreated ones in activating solutions of physiological ionic strength (200 mM); this difference was attributed to the decline of process (A) with EDC treatment. Consequently, the Nyquist plot of the EDC-treated preparation exhibited an insect-type response. We conclude that, under these conditions, both cross-linked and non-cross-linked myosin heads contribute to the production of oscillatory power. The cross-linked preparations also exhibited oscillatory work in high ionic strength (500–1,000 mM) solutions, indicating that cross-linked myosin heads are capable of utilizing ATP to produce work. We conclude that process (A) does not relate to an elementary step in a cross-bridge cycle, but it may relate to dynamics outside the cross-bridge such as filament sliding or sarcomere rearrangement.