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| Study on the Conformational Stability of a Ribonuclease |
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| DOI：10.3969/j.issn.1004-4957.年份.月份 |
| KeyWord:ribonuclease conformational stability UV fluorescence spectrum FT-IR |
| Author | Institution |
| 熊亚红，邓乃康，简晓亮，陈祖强，周建平 |
华南农业大学理学院生物材料研究所 |
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| Abstract: |
| Aspergillus niger SA-13-20 is a new ribonuclease(RNase) isolated from the extracellular enzymes secreted by a mutant named A-niger SA-13-20.The conformational stability of A-niger SA-13-20 ribonuclease at different pH was studied by ultraviolet(UV)，fluorescence and Fourier transform infrared(FT-IR) spectroscopic techniques.UV and fluorescence spectra showed that the conformation of this protein was stable at acid and weak alkali pH，but unstable at pH above 9.6.The secondary structure of the RNase was determined based on the analysis of amide Ⅰ band of FT-IR spectra by using deconvolution and curve fitting technology.The results showed that the percentages of α-helix，β-sheet，turn angle and unordered structure were 13.28%，42.30%，26.48% and 17.95% at pH 5.0 at room temperature，respectively.Melting temperature(Tm)，melting entropy(ΔSm) and melting enthalpy(ΔHm) of this RNase were 70.1 ℃，644 J?mol-1?K-1 and 22.1 kJ?mol-1，respectively，which indicated that the RNase belonged to a ribonuclease with higher heat tolerance.These results are helpful to understand the relationship between the structure and the function of this enzyme，and propel its application in the scientific research and industrial production. |
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