Studies on the lysine-binding sites of human plasminogen. The effect of ligand structure on the binding of lysine analogs to plasminogen.
Studies on the lysine-binding sites of human plasminogen. The effect of ligand structure on the binding of lysine analogs to plasminogen.
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人纤溶酶原赖氨酸结合位点的研究。
DOI：
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发表时间：
1980
期刊：
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通讯作者：
R. Laursen
中科院分区：
文献类型：
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作者：
E. Winn;S. P. Hu;S. Hochschwender;R. Laursen
描述了一种用于测量赖氨酸和赖氨酸类似物与纤溶酶原和纤溶酶原“kringle”片段的相对结合常数的方法。吸附在赖氨酸-琼脂糖上的纤溶酶原或kringle片段用浓度增加的赖氨酸或其它配体洗脱，将50%蛋白质所需的配体浓度作为结合常数的量度。该方法简单，不依赖于监测构象变化。我们证实了早先的报道，纤溶酶原的赖氨酸结合位点的最佳配体是含有五个或六个碳的ω-氨基酸。我们进一步表明，Glu-纤溶酶原（天然形式与N-末端谷氨酸）和赖氨酸-纤溶酶原（降解形式与N-末端赖氨酸），以及重链片段，kringle 4和kringle 1+2+3，具有非常相似的特性方面的结合特异性的ω-氨基酸。对于所有物种，当氨基和羧基碳之间的距离约为0.68 nm时，观察到最佳结合。由于氨基酸碳链的α和β位上存在极性原子，配体的发现减少。精氨酸在赖氨酸位点的结合相对较弱，并且在纤溶酶原中似乎没有单独的精氨酸结合位点。
A method is described for measuring relative binding constants of lysine and analogs of lysine to plasminogen and plasminogen 'kringle' fragments. Plasminogen or kringle fragments adsorbed to lysine-Sepharose are eluted with increasing concentrations of lysine or other ligands, the concentration of ligand required to elute 50% of the protein being taken as a measure of the binding constant. The method is simple and is not dependent on monitoring conformational changes. We confirm earlier reports that the best ligands for the lysine binding sites of plasminogen are omega-amino acids containing five or six carbons. We show further that both Glu-plasminogen (the native form with N-terminal glutamic acid) and Lys-plasminogen (a degraded form with N-terminal lysine), as well as the heavy chain fragments, kringle 4 and kringle 1+2+3, have very similar properties with regard to binding specificity for omega-amino acids. For all species optimal binding is observed when the distance between the amino and carboxyl carbon is about 0.68 nm. The finding of ligands is decreased by the presence of polar atoms on the alpha and beta positions of the carbon chain of amino acids. Arginine binds relatively weakly at the lysine site and there does not appear to be a separate arginine binding site in plasminogen.