Fujii T, Watanabe M, Ogoma Y, Kondo Y, Arai T
Department of Functional Polymer Science, Faculty of Textile Science and Technology, Shinshu University, Nagano.
J Biochem. 1993 Dec;114(6):827-9. doi: 10.1093/oxfordjournals.jbchem.a124263.
Microtubule-associated protein (MAP) 1 consisting of MAP 1A and 1B was purified from rat brain by the poly-L-aspartic acid (PLAA) method. We found that MAP 1 bound to F-actin in vitro up to a molar ratio of MAP 1 to actin monomers of 1:10. The apparent binding constant was about 2.7 x 10(7) M-1. In contrast to the binding of MAP 2 or tau to F-actin, the binding of MAP 1 to F-actin did not affect the low-shear viscosity of actin filaments. Binding experiments performed using fragments of MAP 1, obtained by chymotrypsin digestion, indicated that MAP 1 included binding domains to F-actin that were different from those in microtubules and also two light chains (31 and 29 kDa) that were cosedimented with F-actin as well as with microtubules.
通过聚-L-天冬氨酸（PLAA）法从大鼠脑中纯化出由MAP 1A和MAP 1B组成的微管相关蛋白（MAP）1。我们发现，在体外，MAP 1与F-肌动蛋白结合，MAP 1与肌动蛋白单体的摩尔比高达1:10。表观结合常数约为2.7×10⁷ M⁻¹。与MAP 2或tau与F-肌动蛋白的结合不同，MAP 1与F-肌动蛋白的结合不影响肌动蛋白丝的低剪切粘度。使用胰凝乳蛋白酶消化获得的MAP 1片段进行的结合实验表明，MAP 1包含与微管中不同的F-肌动蛋白结合结构域，以及两条轻链（31 kDa和29 kDa），它们与F-肌动蛋白以及微管一起共沉降。
