Miki M, Barden J A, dos Remedios C G, Phillips L, Hambly B D
Eur J Biochem. 1987 May 15;165(1):125-30. doi: 10.1111/j.1432-1033.1987.tb11202.x.
Modification of Tyr-69 with tetranitromethane impairs the polymerizability of actin in accordance with the previous report [Lehrer, S. S. and Elzinga, M. (1972) Fed. Proc. 31, 502]. Phalloidin induces this chemically modified actin to form the same characteristic helical thread-like structure as normal F-actin. The filaments bind myosin heads and activate the myosin ATPase activity as effectively as normal F-actin. When a dansyl group is introduced at the same point [Chantler, P. D. and Gratzer, W. B. (1975) Eur. J. Biochem. 60, 67-72], phalloidin still induces the polymerization. The filaments bind myosin heads and activate the myosin ATPase activity. These results indicate that Tyr-69 is not directly involved in either an actin-actin binding site or the myosin binding site on actin. Moreover, the results suggest that phalloidin binds to actin monomer in the presence of salt and its binding induces a conformational change in actin which is essential for polymerization, or that actin monomer fluctuates between in unpolymerizable and polymerizable form while phalloidin binds to actin only in the polymerizable form and its binding locks the conformation which causes the irreversible polymerization of actin. Modification of Tyr-53 with 5-diazonium-(1H)tetrazole blocks actin polymerization [Bender, N., Fasold, H., Kenmoku, A., Middelhoff, G. and Volk, K. E. (1976) Eur. J. Biochem. 64, 215-218]. Phalloidin is unable to induce the polymerization of this modified actin nor does it bind to it. Phalloidin does not induce the polymerization of the trypsin-digested actin core. These results indicate that the site at which phalloidin binds is involved in polymerization and the probable conformational change involved in polymerization may be modulated through this site.
根据之前的报道[Lehrer, S. S.和Elzinga, M. (1972) Fed. Proc. 31, 502]，用四硝基甲烷修饰酪氨酸-69会损害肌动蛋白的聚合能力。鬼笔环肽能诱导这种化学修饰的肌动蛋白形成与正常F-肌动蛋白相同的特征性螺旋丝状结构。这些细丝结合肌球蛋白头部，并像正常F-肌动蛋白一样有效地激活肌球蛋白ATP酶活性。当在同一点引入丹磺酰基团时[Chantler, P. D.和Gratzer, W. B. (1975) Eur. J. Biochem. 60, 67 - 72]，鬼笔环肽仍能诱导聚合。这些细丝结合肌球蛋白头部并激活肌球蛋白ATP酶活性。这些结果表明，酪氨酸-69不直接参与肌动蛋白-肌动蛋白结合位点或肌动蛋白上的肌球蛋白结合位点。此外，结果表明，在有盐存在的情况下，鬼笔环肽与肌动蛋白单体结合，其结合诱导肌动蛋白发生构象变化，这对聚合至关重要；或者肌动蛋白单体在不可聚合和可聚合形式之间波动，而鬼笔环肽仅与可聚合形式的肌动蛋白结合，其结合锁定构象，导致肌动蛋白不可逆聚合。用5-重氮基-(1H)四唑修饰酪氨酸-53会阻止肌动蛋白聚合[Bender, N., Fasold, H., Kenmoku, A., Middelhoff, G.和Volk, K. E. (1976) Eur. J. Biochem. 64, 215 - 218]。鬼笔环肽既不能诱导这种修饰的肌动蛋白聚合，也不能与之结合。鬼笔环肽不能诱导胰蛋白酶消化的肌动蛋白核心聚合。这些结果表明，鬼笔环肽结合的位点参与聚合，并且聚合过程中可能涉及的构象变化可能通过该位点进行调节。
