Gee M A, Heuser J E, Vallee R B
Worcester Foundation for Biomedical Research, Shrewsbury, Massachusetts 01545, USA.
Nature. 1997 Dec 11;390(6660):636-9. doi: 10.1038/37663.
Flagellar dynein was discovered over 30 years ago as the first motor protein capable of generating force along microtubules. A cytoplasmic form of dynein has also been identified which is involved in mitosis and a wide range of other intracellular movements. Rapid progress has been made on understanding the mechanism of force production by kinesins and myosins. In contrast, progress in understanding the dyneins has been limited by their great size (relative molecular mass 1,000K-2,000K) and subunit complexity. We now report evidence that the entire carboxy-terminal two-thirds of the 532K force-producing heavy chain subunit is required for ATP-binding activity. We further identify a microtubule-binding domain, which, surprisingly, lies well downstream of the entire ATPase region and is predicted to form a hairpin-like stalk. Direct ultrastructural analysis of a recombinant fragment confirms this model, and suggests that the mechanism for dynein force production differs substantially from that of other motor proteins.
鞭毛动力蛋白在30多年前被发现，是第一种能够沿微管产生力的驱动蛋白。还鉴定出一种细胞质形式的动力蛋白，它参与有丝分裂和广泛的其他细胞内运动。在理解驱动蛋白和肌球蛋白产生力的机制方面已经取得了迅速进展。相比之下，由于动力蛋白体积巨大（相对分子质量为1000K - 2000K）且亚基复杂，在理解动力蛋白方面的进展有限。我们现在报告证据表明，532K产生力的重链亚基的整个羧基末端三分之二是ATP结合活性所必需的。我们进一步鉴定出一个微管结合结构域，令人惊讶的是，它位于整个ATP酶区域的下游很远位置，预计会形成一个发夹状的柄。对一个重组片段的直接超微结构分析证实了这个模型，并表明动力蛋白产生力的机制与其他驱动蛋白有很大不同。
