4QLW

Azurin mutant M121E with iron

Summary for 4QLW

• Entry DOI: 10.2210/pdb4qlw/pdb
• Related: 4QKT
• Descriptor: Azurin, SULFATE ION, NITRATE ION, ... (5 entities in total)
• Functional Keywords: azurin, m121e, iron, electron transport
• Biological source: Pseudomonas aeruginosa
• Cellular location: Periplasm: P00282
• Total number of polymer chains: 4
• Total formula weight: 56858.80

Authors

Liu, J.,Robinson, H.,Lu, Y. (deposition date: 2014-06-13, release date: 2014-08-13, Last modification date: 2024-11-06)

Primary citation

Liu, J.,Meier, K.K.,Tian, S.,Zhang, J.L.,Guo, H.,Schulz, C.E.,Robinson, H.,Nilges, M.J.,Munck, E.,Lu, Y.
Redesigning the Blue Copper Azurin into a Redox-Active Mononuclear Nonheme Iron Protein: Preparation and Study of Fe(II)-M121E Azurin.
J.Am.Chem.Soc., 136:12337-12344, 2014

PubMed Abstract: Much progress has been made in designing heme and dinuclear nonheme iron enzymes. In contrast, engineering mononuclear nonheme iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.

PubMed: 25082811
DOI: 10.1021/ja505410u

Experimental method

X-RAY DIFFRACTION (2 Å)