9DTI

F33Y CuBMb

Summary for 9DTI

• Entry DOI: 10.2210/pdb9dti/pdb
• Related: 9DTH
• Descriptor: Myoglobin, PROTOPORPHYRIN IX CONTAINING FE, DI(HYDROXYETHYL)ETHER, ... (6 entities in total)
• Functional Keywords: oxidase, metalloenzyme, oxidoreductase
• Biological source: Physeter catodon (sperm whale)
• Total number of polymer chains: 1
• Total formula weight: 18252.23

Authors

Lu, Y.,Liu, Y. (deposition date: 2024-10-01, release date: 2025-10-15, Last modification date: 2025-10-29)

Primary citation

Liu, Y.,Vilbert, A.C.,Ghosh, B.,Young, R.P.,Merkley, E.D.,Mukherjee, A.,Phan, L.,Van Stappen, C.,Baghi-Damodaran, A.,Miner, K.D.,Adkins, J.,Cort, J.,Lu, Y.
A Post-translational Histidine-Histidine Cross-Link Enhances Enzymatic Oxygen Reduction Activity with Greater pH Adaptability.
J.Am.Chem.Soc., 147:37688-37700, 2025

PubMed Abstract: Cross-linked protein residues exist as enzyme cofactors to enable or enhance catalytic activities. Despite their importance in nature, the chemical identity of the cross-links is limited to certain amino acid combinations, whose function and the formation mechanism remain insufficiently understood due to the difficulty in isolating native enzymes without the cross-links. Herein, we report the formation and characterization of both His-Tyr and His-His cross-links under oxidative enzymatic turnover conditions in L29H/F33Y/F43H Mb, a structural and functional model of heme-copper oxidase (HCO). The connectivity of the cross-link was characterized as N(His29)-C(His43) by mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR). Interestingly, formation of the cross-link significantly enhances the oxygen reduction activity of the enzyme at neutral or basic pH with higher product specificity. X-ray crystallography has identified a novel Tyr-His cross-link through a Tyr-O-His linkage. Our mechanistic studies indicate the involvement of high-valent heme-iron and the neighboring tyrosine in an oxidative self-processing pathway to generate the cross-link. This work serves as a new example while providing insights into the enzyme cross-link formation, allowing the design of artificial biocatalysts containing these novel cross-links with higher activity and pH adaptability.

PubMed: 41047894
DOI: 10.1021/jacs.5c12710

Experimental method

X-RAY DIFFRACTION (1.681 Å)