Dombrowsky O, Karin C, Schneiderhahn C
Institut für Biophysik, Ruhr-Universität Bochum, Universitätsstrasse 150, W-4630, F.R.G.
Eur Biophys J. 1991;20(5):293-303. doi: 10.1007/BF00450565.
Heisenberg spin exchange rates and dipole-dipole spin lattice relaxation rates for deuterated 14N- and 15N-spin labels bound selectively to the histidine His15 and to the lysines Lys13, 96, 97 of the lysozyme molecule have been determined with the aid of electron spin resonance spectroscopy. The results can be interpreted in terms of a two dimensional translational diffusion of the nitroxide tips of the spin labels along the protein surface within restricted surface areas. The spin labels are regarded as models for long amino acid side chains and as probes for the dynamics of protein and water in the vicinity of the protein surface. The translational diffusion coefficient DII is reduced by a factor of between six and thirty compared to the value for T = 295 K is given by (1.3 +/- 0.6) x 10 -10m2s-1 greater than or equal to DII greater than or equal to (2.4 +/- 0.3) x 10-11M2s-1.
借助电子自旋共振光谱法，已测定了选择性结合到溶菌酶分子中组氨酸His15以及赖氨酸Lys13、96、97上的氘代14N和15N自旋标记的海森堡自旋交换速率和偶极-偶极自旋晶格弛豫速率。结果可用自旋标记的氮氧化物末端在受限表面区域内沿蛋白质表面的二维平移扩散来解释。自旋标记被视为长氨基酸侧链的模型以及蛋白质表面附近蛋白质和水动力学的探针。与T = 295 K时的值相比，平移扩散系数DII降低了6至30倍，其值为(1.3 +/- 0.6) x 10 -10m2s-1≥DII≥(2.4 +/- 0.3) x 10-11M2s-1。
