What is the binding protein for zinc?
The zinc-binding protein p53, a well-known tumor suppressor, plays a critical role in the repression of tumorigenesis by triggering cell cycle arrest, cellular senescence, or cell death by apoptosis in response to a wide range of cellular stresses such as oxidative DNA damage and activated oncogenes.
What do zinc finger domains bind to?
The zinc-finger domain is one of the most frequently utilized DNA-binding motif found in eukaryotic transcriptional factors. The binding of a zinc-finger domain to its target site juxtaposes three base pairs on DNA to a few amino acids in the α-helix structure.
What is zinc ion binding?
Zinc-finger structure, in which a Zn2+ ion binds to four cysteines or histidines in a tetrahedral structure, is a very common motif of nucleic acid-binding proteins. The corresponding interaction model is present in 3% of the genes in the human genome.
How does histidine bind to zinc?
The first involves carbonic anhydrase II where the free N-H groups on the imidazoles from each of the three zinc-bound histidine residues donates a hydrogen bond to a protein-derived oxygen atom. These secondary interactions help stabilize the zinc-binding site, leading to increased zinc affinity and kinetic stability.
What is the binding protein that helps in the absorption of vitamin A?
Retinol-binding protein
Retinol-binding protein (RBP) is a 21-kDa protein that is hepatically synthesized and responsible for transporting vitamin A from the liver to other tissues.
What protein contains a zinc finger domain?
Abstract. Zinc finger domains are one of the most common structural motifs in eukaryotic cells, which employ the motif in some of their most important proteins (including TFIIIA, CTCF, and ZiF268). These DNA binding proteins contain up to 37 zinc finger domains connected by flexible linker regions.
How does cysteine bind to zinc?
Beyond structural roles, cysteines bind Zn2+ to directly facilitate enzymatic transformations. Cysteines are less common ligands in catalytic Zn2+ complexes due to the steric bulk of sulfur and greater charge transfer compared to histidine and water ligands [13].
What blocks zinc absorption?
Phytate, which is a natural component of plants, severely decreases intestinal zinc bioavailability and is regarded as the main nutritional inhibitor of zinc absorption.
What is the function of retinol-binding protein?
To meet vitamin A requirements of tissues, the liver secretes retinol (vitamin A alcohol) into the circulation bound to its sole specific carrier protein, retinol-binding protein (RBP). The single known function of this protein is to transport retinol from the hepatic stores to target tissues.
Which amino acids bind zinc?
Common Zn2+ ligands found within proteins include cysteine (S), histidine (N), aspartate (O), and glutamate (O) residues. The ionization state of the thiol group of cysteine governs its ability to bind metals, including Zn2+.
What are zinc finger and helix turn helix proteins?
Four distinct structural motifs have been proposed for the DNA-binding domains of eukaryotic transcriptional regulatory proteins; the helix-turn-helix, two kinds of zinc finger, and the leucine zipper.
Which amino acids bind to zinc?
Cysteine residues are known to perform essential functions within proteins, including binding to various metal ions. In particular, cysteine residues can display high affinity toward zinc ions (Zn2+), and these resulting Zn2+-cysteine complexes are critical mediators of protein structure, catalysis and regulation.
What is histidine responsible for?
Histidine is required for synthesis of proteins. It plays particularly important roles in the active site of enzymes, such as serine proteases (e.g., trypsin) where it is a member of the catalytic triad. Excess histidine may be converted to trans-urocanate by histidine ammonia lyase (histidase) in liver and skin.
Why do we need histidine?
Histidine is an amino acid most people get from food. It’s used in growth, repair of damaged tissues, and making blood cells. It helps protect nerve cells. It’s used by the body to make histamine.
What causes poor zinc absorption?
Problems with the guts can lead to problems absorbing zinc. This includes gut conditions such as ulcerative colitis, Crohn’s disease, and coeliac disease, and conditions where there is persisting diarrhoea. People who drink excessive alcohol can also not absorb zinc normally.
What helps zinc get into cells?
The uptake of zinc into cells and its transport into and out of intracellular organelles requires transporter proteins that span these membranes to facilitate the movement of zinc. Zinc transporters belong to at least 6 different transporter families.
How does zinc bind to proteins and solution?
Zinc binding in proteins and solution: a simple but accurate nonbonded representation Force field parameters that use a combination of Lennard-Jones and electrostatic interactions are developed for divalent zinc and tested in solution and protein simulations.
How common are zinc-binding sites in proteins?
Approximately 10% of proteins require zinc to function [ 1] and so have at least one zinc binding site, making it the second-most prevalent metal in biological systems, after iron.
What is the mechanism of zinc binding and release in SBPs?
As such, the mechanisms of zinc binding and release among bacterial SBPs are of considerable interest as antibacterial drug targets. Zinc SBPs are characterized by a flexible loop near the high-affinity zinc-binding site.
Why are zinc binding sites harder to detect in apo proteins?
The model’s performance in holo proteins indicates that it is able to detect zinc binding sites when the side chains are ideally arranged to bind the metal. In an apo protein structure, however, a binding site’s side chains are more likely to take on alternate conformations, making the site harder to detect.