Babiychuk E B, Babiychuk V S, Sobieszek A
Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg.
Biochemistry. 1995 May 16;34(19):6366-72. doi: 10.1021/bi00019a015.
Oligomerization of turkey gizzard myosin light chain kinase (MLCKase) was demonstrated by a zero-length cross-linker, 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC), a standard reagent used in investigations of specific protein-protein interaction [Mornet et al. (1989) J. Muscle Res. Cell Motil. 10, 10-24]. This approach revealed that in solution the kinase was not monomeric but the monomers were in equilibrium with the kinase dimeric and oligomeric forms. Addition of Ca2+/calmodulin (CM) shifted this equilibrium in the direction of the kinase dimers, accompanied by a 2-fold decrease of the kinase catalytic activity, in addition to a 2-fold decrease of its apparent affinity for CM [Sobieszek et al. (1993) Biochem. J. 295, 405-411]. The dimer (and/or oligomer) formation was shown to result from an interaction of the kinase autoinhibitory domain with its 24 kDa tryptic fragment containing titin-like domain II-3. The possible significance of the oligomerization in regulation of MLCKase activity is discussed.
火鸡砂囊肌球蛋白轻链激酶（MLCKase）的寡聚化通过零长度交联剂盐酸1-乙基-3-[3-(二甲氨基)丙基]碳二亚胺（EDC）得以证明，EDC是用于研究特定蛋白质-蛋白质相互作用的标准试剂[莫内特等人（1989年）《肌肉研究与细胞运动》10卷，10 - 24页]。这种方法表明，在溶液中该激酶并非单体形式，而是单体与激酶二聚体和寡聚体形式处于平衡状态。添加Ca²⁺/钙调蛋白（CM）会使这种平衡向激酶二聚体方向移动，除了其对CM的表观亲和力降低2倍外，激酶催化活性还降低2倍[索别谢克等人（1993年）《生物化学杂志》295卷，405 - 411页]。已证明二聚体（和/或寡聚体）的形成是由于激酶自身抑制结构域与其含有肌联蛋白样结构域II - 3的24 kDa胰蛋白酶片段相互作用所致。文中讨论了寡聚化在MLCKase活性调节中的可能意义。
