Incorporation of the red copper nitrosocyanin binding loop into blue copper azurin

Protein Design: Toward Functional Metalloenzymes

“…359 A red copper center was also introduced into Az, without using unnatural amino acids, by substituting the blue copper-binding loop with a red copper-binding loop from nitrosocyanin using loop-directed mutagenesis. 441 …”

Site-directed mutagenesis of the highly perturbed copper site of auracyanin D

“…We decided to check if auracyanin D was generally more sensitive to axial ligand substitutions than other BCPs, and created the Q121H and Q121L mutations. Q121H had a red appearance similar to nitrosocyanin [11] and azurin M121H [16,30]. The spectrum was highly perturbed (Fig.…”

Effects of mutations on the absorption spectra of copper proteins: a QM/MM study

“…Conversely, the influence of the fixed charges on classical atoms can be easily evidenced by setting them to zero and performing another QM computation on the previously optimized fixed geometry. The electronic response of the surroundings (ERS) [26,[31][32][33][34] technique allows us to simulate the role of electronic polarization, that is, the modifications of the electronic distribution of the classical subsystem treated at MM level under the influence of the density modification in the QM part. Indeed, if within the framework of the Franck-Condon principle, the electronic transitions are vertical and do not involve any nuclear position rearrangement, the electronic cloud of the environment can, however, instantaneously adapt itself to the new electronic distribution of the chromophore.…”

“…Technically, the chromophore is placed in a site cavity created in the continuum and the MM points charges of the protein do not interact with the continuum. ERS technique already proved its efficiency in modeling the important effects of electronic polarizability on the position and intensities of electronic transitions, at a very moderate additional computational cost [26,[31][32][33][34]]. …”

“…Recently, the effect of the mutation of the methionine ligand on the absorption spectrum of the blue-copper proteins has been underlined and proved experimentally [13], as well as the artificial mutation of the active site loop sequence of plastocyanin with the nitrosocyanin one giving rise to a red-copper protein [31].…”