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Updated: Mar 13, 2026
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Effect of circular permutation on the structure and function of type 1 blue copper center in azurin
Yang Yu1, Igor D Petrik2, Kelly N Chacón3
1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Abstract:
Type 1 copper (T1Cu) proteins are electron transfer (ET) proteins involved in many important biological processes. While the effects of changing primary and secondary coordination spheres in the T1Cu ET function have been extensively studied, few report has explored the effect of the overall protein structural perturbation on active site configuration or reduction potential of the protein, even though the protein scaffold has been proposed to play a critical role in enforcing the entatic or "rack-induced" state for ET functions. We herein report circular permutation of azurin by linking the N- and C-termini and creating new termini in the loops between 1st and 2nd β strands or between 3rd and 4th β strands. Characterization by electronic absorption, electron paramagnetic spectroscopies, as well as crystallography and cyclic voltammetry revealed that, while the overall structure and the primary coordination sphere of the circular permutated azurins remain the same as those of native azurin, their reduction potentials increased by 18 and 124 mV over that of WTAz. Such increases in reduction potentials can be attributed to subtle differences in the hydrogen-bonding network in secondary coordination sphere around the T1Cu center.
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