Teng T Y, Srajer V, Moffat K
Department of Biochemistry and Molecular Biology, University of Chicago, IL 60637, USA.
Nat Struct Biol. 1994 Oct;1(10):701-5. doi: 10.1038/nsb1094-701.
Myoglobin's reversible binding of oxygen is a model for studies of protein control of ligand binding and discrimination. Protein relaxation and geminate ligand rebinding subsequent to ligand photodissociation have been studied extensively by a variety of techniques. The ps to ns time scales for these processes are still much shorter than the ms time resolution of X-ray diffraction experiments, but it may be possible to trap these intermediates at low temperatures. We report here an X-ray diffraction investigation of structural changes induced by photolysis of carbonmonoxy myoglobin crystals at 40 K. Our results provide a structural basis for the interpretation of ambient and low temperature spectroscopic observations and molecular dynamics simulations of the ligand photodissociation and binding processes in haem proteins.
肌红蛋白对氧的可逆结合是研究蛋白质对配体结合与识别控制的一个模型。配体光解离后蛋白质弛豫和双生配体重结合已通过多种技术进行了广泛研究。这些过程从皮秒到纳秒的时间尺度仍比X射线衍射实验的毫秒级时间分辨率短得多，但有可能在低温下捕获这些中间体。我们在此报告一项关于在40 K下光解一氧化碳肌红蛋白晶体所诱导结构变化的X射线衍射研究。我们的结果为解释血红蛋白中配体光解离和结合过程的常温及低温光谱观测以及分子动力学模拟提供了结构基础。
