Spectroscopic Characterization of Staphylococcal Nuclease Mutants with Tryptophan at Internal Sites
GAO Guang-Yu1, LI Yu1, WANG Wei1, ZHONG Dong-Ping2, WANG Shu-Feng1**, GONG Qi-Huang1
1Institute of Modern Optics & State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 2Department of Physics, Department of Chemistry and Biochemistry, and Programs of Biophysics, Chemical Physics and Biochemistry, The Ohio State University, OH 43210, USA
Abstract：Tryptophan (Trp) is an intrinsic fluorescent probe for detecting the site-specified dynamics inside/outside protein. It is found that the Trp can easily be inserted in desired sites of protein, which affects the integrity of the overall structure. To evaluate this effect, we design thirteen double point mutants of staphylococcal nuclease, each of which has a single Trp residue planted at an internal site. The studies on Trp fluorescence, ANS-binding fluorescence, far- and near-UV CD spectra, and enzymatic activity are carried out. It is found that the mutation at the hydrophobic core of protein generates molten globular state conformation, which is a loose structure compared to their original compactness in wild type (WT). Its enzyme activity and surface hydrophobicity are also affected. The studies show that by proper site designing and external binding, Trp mutagenesis is a suitable method for carrying out the study on site specified dynamics of proteins.
. [J]. 中国物理快报, 2015, 32(4): 48701-048701.
GAO Guang-Yu, LI Yu, WANG Wei, ZHONG Dong-Ping, WANG Shu-Feng, GONG Qi-Huang. Spectroscopic Characterization of Staphylococcal Nuclease Mutants with Tryptophan at Internal Sites. Chin. Phys. Lett., 2015, 32(4): 48701-048701.
2015, Vol. 32 
