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Recognition of α-Helix in Denature Protein by Iron(III) Complexes and Mechanism of Hydrolysis

Author: XiaQingFeng
Tutor: LiuChangLin
School: Huazhong University of Science and Technology
Course: Inorganic Chemistry
Keywords: iron complex hydrolysis structure recognition
CLC: Q51
Type: Master's thesis
Year: 2007
Downloads: 32
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Abstract

There was obvious relationship between structure and function of protein. We can predict the protein’function in the biologic system according to its structure, and design protein for treating some disease. Therefore, it’s significant to determine structure of protein. To date, determination of three-dimensional structures of proteins was mainly dependent on X-ray crystallography and multi-dimensional nuclear magnetic resonance (NMR). However, their limitation was very obvious. The protein’s proteolysis has widely been accepted as probe for proteins’structure several years ago. But the synthetical reagents and proteases were mostly used to proteolysis that is residue-specific and could only probe the primary structure.The information of secondary and advanced structure of proteins was little.The requirement of hydrolysis of protein was binded to complex, then the nucleophiles attacked leading to hydrolysis of peptides bonds of protein. In this work, the binding interaction between each iron complex and proteins were firstly examined by UV-visible absorption and fluorescence spectra. The apparent binding constants of Fe2 or Fe4 to denatured proteins were obtained. We found that the parameter of denatured proteins was enlarged than natural proteins. Fe2 or Fe4 could quench the fluorescence intensity of tryptophan residues in BSA and Lyso. But their styles of quenching were not the same. Fe2 quenched the fluorescence of intensity of proteins by static quenching style at room temperature, and Fe4 by combined quenching style. On the other hand, the fluorescence intensity of proteins was determined at different time in hydrolysis process mediated by Fe2 or Fe4.On the other hand, the products of hydrolysis of BSA, Lyso, Hb, RNase in different pH were analyzed by SDS-PAGE, by changing the concentration of proteins, we got the kinetic equation of hydrolysis. The products of BSA hydrolyzed catalyzed by Fe4 at pH 7.6 was examined by LC-MS. The result demonstrated that the BSA hydrolysis catalyzed by Fe4 may be the domain-specific at low and high pH.The results indicated that Fe4 maybe can be used to obtain the basic information of secondary structure of proteins.

Recognition of α-Helix in Denature Protein by Iron(III) Complexes and Mechanism of Hydrolysis

Abstract

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