Orientation of actin monomer in the F-actin filament: radial coordinate of glutamine-41 and effect of myosin subfragment 1 binding on the monomer orientation.
Orientation of actin monomer in the F-actin filament: radial coordinate of glutamine-41 and effect of myosin subfragment 1 binding on the monomer orientation.
复制标题
F-肌动蛋白丝中肌动蛋白单体的方向：谷氨酰胺 41 的径向坐标和肌球蛋白亚片段 1 结合对单体方向的影响。
DOI：
10.1021/bi00412a044
复制
发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Morales,MF
中科院分区：
文献类型：
--
作者：
Kasprzak,AA;Takashi,R;Morales,MF
摘要：我们采用了径向距离测量的方法，以确定肌动蛋白单体在F-肌动蛋白丝中的方向。该方法利用荧光共振能量转移测量位于两个不同单体上的两个等效化学点之间的距离。用这种方法获得的探针间距离计算标记氨基酸的径向坐标[Taylor，D. L.，Reidler，J.，Spudich，J. A.，& Stryer，L.（1981）J. Cell Biol.89，362-367]，理论分析表明，如果确定四个点的径向坐标并且已知六个分子内距离，则可以在对称限度内将单体定位在丝轴周围。发现用丹磺酰基、罗丹明和尸胺的荧光素衍生物酶促修饰的Gln-41的径向距离约为40-42 nm。以单溴异丙亚胺和7-[[（碘乙酰基）氨基]乙基]-5-萘胺-1-磺酸盐为供体，N-[4-[[4-（二甲氨基）苯基]唑苯基]马来酰亚胺为受体，测定了Cys-374的径向距离，结果与该残基的径向坐标20-25 A一致。还检查了肌球蛋白亚片段1（SI）结合对（1）Gln-41、（2）Cys-374和（3）核苷酸结合位点的径向坐标的影响。SI对Gln-41的径向坐标影响较小，使其增加到44-47 A。在剩下的两种情况下，由于Si的结合而引起的径向坐标的变化可以忽略不计。这一发现排除了肌动蛋白和SI之间相互作用的某些模型，其中肌动蛋白单体在亚片段1结合时旋转一个大角度。
Revised Manuscript Received February 9, 1988 abstract: We have employed the method of radial distance measurements in order to orient the actin monomer in the F-actin filament. This method utilizes fluorescence resonance energy transfer measurements of the distance between two equivalent chemical points located on two different monomers. The interprobe distance obtained this way is used tocompute the radial coordinate of the labeled amino acid [Taylor, D. L., Reidler, J., Spudich, J. A., & Stryer, L.(1981) J. Cell Biol. 89, 362-367], Theoretical analysis has indicated that if radial coordinates of four points are determined and six intramolecular distances are known, one can, within symmetry limits, position the monomer about the filament axis. The radial distance of Gln-41 that had been enzymatically modified with dansyl, rhodamine, and fluorescein derivatives of cadaverine was found to be approximately 40-42 Á. The determination of the radial distance of Cys-374 was ac-complished by using monobromobimane and 7V-[[(iodoacetyl) amino] ethyl]-5-naphthylamine-l-sulfonate as donors and N-[4-[[4-(dimethylamino) phenyl] azolphenyl] maleimide as acceptor; the results were consistent with a radial coordinate for this residue of 20-25 A. The effect of myosin subfragment 1 (SI) binding on the radial coordinates of (1) Gln-41,(2) Cys-374, and (3) the nucleotide binding site was also examined. SI had a small effect on the radial coordinate of Gln-41, increasing it to 44-47 A. In thetwo remaining cases the change in the radial coordinate due to the Si binding was negligible. This finding excludes certain models of the interaction between actin and SI in which actin monomer rotates by a large angle when subfragment 1 binds to it.