6Z4R

sperm whale myoglobin mutant (H64V V64A) bearing the non-canonical amino acid 3-thienylalanine as axial heme ligand

Summary for 6Z4R

• Entry DOI: 10.2210/pdb6z4r/pdb
• Descriptor: Myoglobin, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: globin, heme protein, enzyme, metal binding protein
• Biological source: Physeter macrocephalus (Sperm whale)
• Total number of polymer chains: 1
• Total formula weight: 17870.50

Authors

Tinzl, M.,Hilvert, D.,Mittl, P.R.E. (deposition date: 2020-05-25, release date: 2021-04-28, Last modification date: 2024-01-24)

Primary citation

Pott, M.,Tinzl, M.,Hayashi, T.,Ota, Y.,Dunkelmann, D.,Mittl, P.R.E.,Hilvert, D.
Noncanonical Heme Ligands Steer Carbene Transfer Reactivity in an Artificial Metalloenzyme*.
Angew.Chem.Int.Ed.Engl., 60:15063-15068, 2021

PubMed Abstract: Changing the primary metal coordination sphere is a powerful strategy for tuning metalloprotein properties. Here we used amber stop codon suppression with engineered pyrrolysyl-tRNA synthetases, including two newly evolved enzymes, to replace the proximal histidine in myoglobin with N -methylhistidine, 5-thiazoylalanine, 4-thiazoylalanine and 3-(3-thienyl)alanine. In addition to tuning the heme redox potential over a >200 mV range, these noncanonical ligands modulate the protein's carbene transfer activity with ethyl diazoacetate. Variants with increased reduction potential proved superior for cyclopropanation and N-H insertion, whereas variants with reduced E values gave higher S-H insertion activity. Given the functional importance of histidine in many enzymes, these genetically encoded analogues could be valuable tools for probing mechanism and enabling new chemistries.

PubMed: 33880851
DOI: 10.1002/anie.202103437

Experimental method

X-RAY DIFFRACTION (1.96 Å)