6 days ago · Histidine’s protonation state is highly sensitive to its surroundings, with local conditions often dictating whether the imidazole ring carries a positive charge. One of the most influential factors is localized pH variation. While bulk solution pH provides a general framework, protein interiors, enzyme active sites, or membrane-associated ...

In catalytic triads, the basic nitrogen of histidine abstracts a proton from serine, threonine, or cysteine to activate it as a nucleophile. In a histidine proton shuttle, histidine is used to quickly shuttle protons.

Jan 5, 2011 · Here we use magic-angle-spinning solid-state NMR spectroscopy to determine the 15 N, 13 C, and 1 H chemical shifts of histidine from pH 4.5 to 11. Two-dimensional homonuclear and heteronuclear correlation spectra indicate that these chemical shifts depend sensitively on the protonation state and tautomeric structure.

Histidine (His) stands out as the most versatile natural amino acid due to its side chain’s facile propensity to protonate at physiological pH, leading to a transition from aromatic to cationic characteristics and thereby enabling diverse biomolecular interactions.

Aug 5, 2024 · The ability of histidine to act as a proton shuttle, facilitating proton transfer reactions between reactants during enzymatic catalysis, underscores its indispensable role in diverse biochemical pathways. Histidine mediated hydrogen bonds can be of crucial functional relevance, as in photosystem II or Pin1.

Protonation at the two N atoms of the imidazole moiety of histidine elicits measurable changes in the heterocyclic ring geometry.

Histidine residues play important structural and functional roles in proteins, such as serving as metal-binding ligands, mediating enzyme catalysis, and modulating proton channel activity. Many of these activities are modulated by the ionization state of the imidazole ring.

Mar 11, 2025 · Explore how protonated histidine influences protein-ligand interactions through structural shifts and metal ion coordination. Understanding the intricacies of protein-ligand interactions is crucial for advancing fields such as drug design and enzymatic function.

Jul 24, 2024 · Histidine (His) stands out as the most versatile natural amino acid due to its side chain's facile propensity to protonate at physiological pH, leading to a transition from aromatic to cationic characteristics and thereby enabling diverse biomolecular interactions.

Jul 22, 2024 · Histidine (His) stands out as the most versatile natural amino acid due to its side chain’s facile propensity to protonate at physiological pH, leading to a transition from aromatic to cationic characteristics and thereby enabling diverse biomolecular interactions.