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The expressed α domain of mouse metallothionein‐I from Escherichia coli displays independent structure and function
Author(s) -
Xiong Yi,
Chen Yiwu,
Ru Binggen
Publication year - 1998
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549800203822
Subject(s) - escherichia coli , metallothionein , function (biology) , domain (mathematical analysis) , chemistry , computational biology , microbiology and biotechnology , biology , biochemistry , gene , mathematics , mathematical analysis
The α domain of mouse metallothionein‐I (mMT‐I) was expressed in E. coli as a C‐terminus of the 26 KD glutathione‐S‐transferase and purified from the cell lysates. The amino acid composition and molecular weight of the expressed protein are as expected. The metal‐binding stoichimetry was determined to show that divalent metals bind to the expressed α domain at the desired ratio of 4:1. The ultraviolet absorbance, circular dichroism spectra and the atomic force microscopy indicate that it can form the proper metal‐thiolate structure as in the whole MT molecule. The apparent affinity of the expressed α domain to bind cadmium is 1.8‐fold stronger than the recombinant mMT‐I when detected by the reaction with DTNB. The ability to scavenge hydroxyl free radicals remains higher than the whole MT molecule. All the results demonstrate that the expressed α‐domain from E. coli exhibits independent biochemical and physiological structure/function without the assistance of β domain.