9jiu
Ferritin mutant R63MeHis
Structural highlights
FunctionFRIH_HUMAN Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Has ferroxidase activity. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation. Also plays a role in delivery of iron to cells. Mediates iron uptake in capsule cells of the developing kidney (By similarity). Publication Abstract from PubMedHistidine modifications of proteins are broadly based on chemical methods triggering N-substitution reactions such as aza-Michael addition at histidine's moderately nucleophilic imidazole side chain. While recent studies have demonstrated chemoselective, histidine-specific modifications by further exploiting imidazole's electrophilic reactivity to overcome interference from the more nucleophilic lysine and cysteine, achieving site-specific histidine modifications remains a major challenge due to the absence of spatial control over chemical processes. Herein, through X-ray crystallography and cryo-electron microscopy structural studies, we describe the rational design of a nature-inspired, noncanonical amino-acid-incorporated, human ferritin-based metalloenzyme that is capable of introducing site-specific post-translational modifications (PTMs) to histidine in peptides and proteins. Specifically, chemoenzymatic aza-Michael additions on single histidine residues were carried out on eight protein substrates ranging from 10 to 607 amino acids including the insulin peptide hormone. By introducing an insulin-targeting peptide into our metalloenzyme, we further directed modifications to be carried out site-specifically on insulin's B-chain histidine 5. The success of this biocatalysis platform outlines a novel approach in introducing residue- and, moreover, site-specific post-translational modifications to peptides and proteins, which may further enable reactions to be carried out in vivo. Site-Specific Histidine Aza-Michael Addition in Proteins Enabled by a Ferritin-Based Metalloenzyme.,Tsou JC, Tsou CJ, Wang CH, Ko AA, Wang YH, Liang HH, Sun JC, Huang KF, Ko TP, Lin SY, Wang YS J Am Chem Soc. 2024 Nov 5. doi: 10.1021/jacs.4c14446. PMID:39499210[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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