Karlsson B G, Nordling M, Pascher T, Tsai L C, Sjölin L, Lundberg L G
Department of Biochemistry and Biophysics, Chalmers University of Technology, Göteborg, Sweden.
Protein Eng. 1991 Feb;4(3):343-9. doi: 10.1093/protein/4.3.343.
Cassette mutagenesis was used to exchange the suggested copper ligand Met121 in azurin to all other amino acids, and a stop codon. The mutant proteins were characterized by optical absorption spectroscopy and EPR. At low pH, all mutants exhibit the characteristics of a blue type 1 copper protein, indicating that methionine is not needed to create a blue copper site. At high pH, the Glu121 and the Lys121 mutants constitute a new form of protein-bound copper that is outside the range of type 1 copper.
利用盒式诱变技术将天青蛋白中建议的铜配体甲硫氨酸121替换为所有其他氨基酸以及一个终止密码子。通过光学吸收光谱和电子顺磁共振对突变蛋白进行了表征。在低pH值下，所有突变体均表现出蓝色1型铜蛋白的特征，这表明形成蓝色铜位点不需要甲硫氨酸。在高pH值下，谷氨酸121和赖氨酸121突变体构成了一种新型的蛋白质结合铜，其不在1型铜的范围内。
