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Spectroscopic investigations on the conformational changes of lysozyme effected by different sizes of N‐acetyl‐ l ‐cysteine‐capped CdTe quantum dots
Author(s) -
Wu Qianqian,
Wan Jingqiang,
He Zhuo,
Liu Rutao
Publication year - 2017
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.21982
Subject(s) - lysozyme , chemistry , cadmium telluride photovoltaics , isothermal titration calorimetry , quantum dot , quenching (fluorescence) , particle size , fluorescence , cysteine , crystallography , biophysics , enzyme , analytical chemistry (journal) , chromatography , biochemistry , nanotechnology , materials science , physics , quantum mechanics , biology
The effect of N‐acetyl‐ l ‐cysteine‐capped CdTe quantum dots (NAC‐CdTe QDs) with different sizes on lysozyme was investigated by isothermal titration calorimetry (ITC), enzyme activity assays, and multi‐spectroscopic methods. ITC results proved that NAC‐CdTe QDs can spontaneously bind with lysozyme and hydrophobic force plays a major role in stabilizing QDs–lysozyme complex. Multi‐spectroscopic measurements revealed that NAC‐CdTe QDs caused strong quenching of the lysozyme's fluorescence in a size‐dependent quenching manner. Moreover, the changes of secondary structure and microenvironment in lysozyme caused by the NAC‐CdTe QDs were higher with a bigger size. The results of enzyme activity assays showed that the interaction between lysozyme and NAC‐CdTe QDs inhibited the activity of lysozyme and the inhibiting effect was in a size‐dependent manner. Based on these results, we conclude that NAC‐CdTe QDs with larger particle size had a larger impact on the structure and function of lysozyme.