Molecular mechanics of mouse cardiac myosin isoforms
Molecular mechanics of mouse cardiac myosin isoforms
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DOI：
10.1152/ajpheart.00274.2002
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发表时间：
2002-10-01
影响因子：
4.8
通讯作者：
Warshaw, DM
中科院分区：
文献类型：
--
作者：
Alpert, NR;Brosseau, C;Warshaw, DM
两种肌球蛋白亚型在心肌中表达，β-同源二聚体（V-1）和β-同源二聚体（V-3）。与V-3相比，V-1表现出更高的速度和肌原纤维ATP酶活性。我们也观察到这一点的心脏肌球蛋白从正常（V-1）和丙基硫氧嘧啶治疗（V-3）小鼠。肌动蛋白的运动性测定（V-肌动蛋白）超过V-1肌球蛋白的速度是两倍的V-3的肌原纤维ATP酶。V-1和V-3的肌球蛋白平均力（F-avg）相似。比较V-I和V-3的跨物种的Vactin和F-avg，我们的实验室先前显示（VanBuren P，Harris DE，Alpert NR和Warshaw DM. Circ Res 77：439-444，1995），小鼠V-1与兔V-1相比具有更大的V-肌动蛋白和F-avg。小鼠V-3V-肌动蛋白是兔V-肌动蛋白的两倍。为了了解肌球蛋白的分子结构和功能，我们比较了啮齿动物和兔子的α-和β-心肌肌球蛋白序列。与啮齿类动物相比，兔子的α-和β-心肌肌球蛋白分别相差8个和4个氨基酸。这些残基定位于运动域和杆。这些序列和机械性能的差异可能是一种进化的尝试，使肌球蛋白的机械行为与心脏的动力需求相匹配。
Two myosin isoforms are expressed in myocardium, betabeta-homodimers (V-1) and betabeta-homodimers (V-3). V-1 exhibits higher velocities and myofibrillar ATPase activities compared with V-3. We also observed this for cardiac myosin from normal (V-1) and propylthiouracil-treated (V-3) mice. Actin velocity in a motility assay (V-actin) over V-1 myosin was twice that of V-3 as was the myofibrillar ATPase. Myosin's average force (F-avg) was similar for V-1 and V-3. Comparing Vactin and F-avg across species for both V-1 and V-3, our laboratory showed previously (VanBuren P, Harris DE, Alpert NR, and Warshaw DM. Circ Res 77: 439-444, 1995) that mouse V-1 has greater V-actin and F-avg compared with rabbit V-1. Mouse V-3 V-actin was twice that of rabbit V-actin. To understand myosin's molecular structure and function, we compared alpha- and beta-cardiac myosin sequences from rodents and rabbits. The rabbit alpha- and beta-cardiac myosin differed by eight and four amino acids, respectively, compared with rodents. These residues are localized to both the motor domain and the rod. These differences in sequence and mechanical performance may be an evolutionary attempt to match a myosin's mechanical behavior to the heart's power requirements.