Histidine Side Chain
Histidine Side Chain - Related Videos
02:57
Inducible Expression of Histidine-Tagged Ricin Toxin A Chain in E. coli
0 Views •
2025
Source: Becker, B., et al. A Simple Fluorescence-based Reporter Assay to Identify Cellular Components Required for Ricin Toxin A Chain (RTA) Trafficking in Yeast. J. Vis. Exp. (2017)This video demonstrates the inducible expression of His-tagged ricin toxin A chain (RTA) in Escherichia coli. It outlines the steps involved in the selective culturing of bacteria transformed with a recombinant expression plasmid, induction of His-tagged RTA expression, and preparation of the bacteria for further...
09:17
Quantification of Bacterial Histidine Kinase Autophosphorylation Using a Nitrocellulose Binding Assay
0 Views •
Cited by 3 •
2017
We report and demonstrate an optimized nitrocellulose binding assay that can be used to quantify autophosphorylation of purified bacterial histidine kinases. Our method has several advantages over traditional SDS-PAGE based techniques, providing a valuable alternative for characterizing these important proteins.
12:52
Iridium(III) Luminescent Probe for Detection of the Malarial Protein Biomarker Histidine Rich Protein-II
0 Views •
Cited by 4 •
2015
Robust detection reagents are of increasing necessity for developing new malaria diagnostic tools. An iridium(III) probe was designed that emits long-lasting luminescent signal in the presence of a histidine-rich malarial protein biomarker. Detection of the protein either in solution or immobilized on a magnetic particle affords flexibility in application.
01:28
Electron Transport Chains
0 Views •
2019
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle. The ETC is comprised of...
01:31
Supply Chain and Supply Chain Management
0 Views •
2025
Individuals, organizations, resources, activities, and technology are all involved in creating and selling a product. The process typically begins with sourcing raw materials from suppliers, progresses through manufacturing to produce finished goods, continues with warehousing, and culminates in distribution to consumers. Supply Chain Management, or SCM oversees the seamless flow of goods, information, and finances across these stages, aiming to optimize costs, manage inventory levels...
FAQs
A histidine side chain can shift between proton-accepting and proton-donating states as pH changes near physiological conditions. That shift alters whether the residue can participate in proton transfer and can change the stabilization of charged intermediates during protein reactions. Consequently, pH-dependent changes in histidine protonation provide a mechanism linking the chemical environment to protein activity.
The imidazole ring gives histidine the reversible acid-base behavior needed for controlled proton exchange. Depending on its protonation state, the ring can accept a proton during one step and donate it during another. This capability allows a histidine residue to support sequential chemical events in an active site rather than serving only as a fixed structural group.
Nitrogen atoms within the histidine imidazole ring can coordinate metal ions, helping position the ion within a protein. This binding can organize the surrounding active site and support metal-dependent molecular interactions. The resulting arrangement is especially relevant to metalloproteins, where the location and coordination of a metal ion are important for the protein's function.
Histidine can help stabilize a charged intermediate through its acid-base behavior and the interactions associated with its protonation state. By accepting or donating a proton, the residue can reduce unfavorable charge changes during a reaction. Within an enzyme active site, this contribution helps connect proton transfer with the progression of catalysis.
Researchers can compare protein behavior under different pH conditions and consider how those conditions alter histidine protonation. A change in activity may reflect loss or gain of proton-transfer capacity, altered stabilization of charged intermediates, or changed metal-related interactions. This interpretation is useful for connecting pH-dependent protein function with specific chemical roles of histidine residues.
Histidine residues provide a link between chemical reactivity, metal coordination, and structural organization. Their nitrogen atoms can help organize metal-containing regions, while their protonation behavior can influence nearby interactions and active-site chemistry. Examining these properties helps explain how a protein maintains functional arrangements and how metal-dependent processes operate within biological systems.