9OH7
M13F/H117A/M121H Azurin with Cu(II), pH 7.4
Summary for 9OH7
| Entry DOI | 10.2210/pdb9oh7/pdb |
| Descriptor | Azurin, 2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, COPPER (II) ION, ... (4 entities in total) |
| Functional Keywords | metal binding mutant azurin protein, oxidoreductase |
| Biological source | Pseudomonas aeruginosa PAO1 |
| Total number of polymer chains | 4 |
| Total formula weight | 56667.58 |
| Authors | |
| Primary citation | Van Stappen, C.,Xu, J.,Liu, Y.,Van Stappen, J.,Kim, W.,Zhang, Y.J.,Lu, Y. Beyond Blue: Systematic Modulation of Electronic Structure and Redox Properties of Type 1 Copper in Azurin. J.Am.Chem.Soc., 147:24825-24837, 2025 Cited by PubMed Abstract: The reduction potentials of metal ions (°'), crucial for optimizing biological processes like electron transfer and catalysis, are finely tuned by interactions between the primary and secondary coordination spheres (PCS, SCS). While previous successes in tuning °' in azurin have provided deeper insights into how the SCS influences electronic structure and associated redox properties of "classic" blue copper proteins, our understanding of °' tuning in other subclasses of type 1 Cu (T1Cu) proteins, such as green and red copper proteins, remains rudimentary. To address this issue, we report the design of a green copper center in azurin where an equatorial-to-axial shift in a histidine binding interaction leads to reorientation of the Cu-centered redox active molecular orbital and a +100 mV shift in °'. In contrast to a 22 mV decrease in °' when a hydrophobic interaction is introduced in wild-type azurin through the Met13Phe mutation, this same mutation leads to a 65 mV increase in our designed green Cu azurin. More importantly, using a combination of EPR spectroscopy, protein crystallography, and quantum mechanical calculations, we uncover correlations between °', d-s orbital mixing, and the angle between S-Cu and N-Cu bonds, ∠(S-Cu-N), allowing rationalization of increases in °' of green Cu proteins through an entropically driven T-shape distortion. By providing direct connections between geometry, electronic structure, and functional properties such as °', this work opens previously unexplored routes to systematically modulating °' through the combination of spatial reorientation of the redox active molecular orbital and varying geometric distortion in the primary coordination sphere. PubMed: 40626760DOI: 10.1021/jacs.5c07009 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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