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Valine ball and stick model spinning. Valine (symbol Val or V) [4] is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH 3 + form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO − form under biological conditions), and a side chain isopropyl group, making it a non-polar ...
The hydrophobic effect depends on the temperature, which leads to "cold denaturation" of proteins. [19] The hydrophobic effect can be calculated by comparing the free energy of solvation with bulk water. In this way, the hydrophobic effect not only can be localized but also decomposed into enthalpic and entropic contributions. [3]
The fact that valine and isoleucine are both beta branched, the beta sheet is their secondary structure of preference. Since both of these amino acids are also hydrophobic this mutation is thought to have little interference with the folding and stability of the protein. The last differentiation in amino acid configuration is at Asn-45/Asp-45 ...
Polar chemical groups, such as OH group in methanol do not cause the hydrophobic effect. However, a pure hydrocarbon molecule, for example hexane, cannot accept or donate hydrogen bonds to water. Introduction of hexane into water causes disruption of the hydrogen bonding network between water molecules.
A tyrosine residue also plays an important role in photosynthesis. In chloroplasts (photosystem II), it acts as an electron donor in the reduction of oxidized chlorophyll. In this process, it loses the hydrogen atom of its phenolic OH-group. This radical is subsequently reduced in the photosystem II by the four core manganese clusters. [11]
Elastic fiber in the body is a mixture of amorphous elastin and fibrous fibrillin. Both components are primarily made of smaller amino acids such as glycine , valine , alanine , and proline . [ 11 ] [ 14 ] The total elastin ranges from 58 to 75% of the weight of the dry defatted artery in normal canine arteries. [ 15 ]
The substituted phenyl group at the top of the channel interacts with the side-chains of amino acid residues through hydrophobic and electrostatic interactions. Tyr385 makes for some sterical restrictions of this side of the binding site so a small substituent of the phenyl group makes for better binding. Degrees of freedom are also important ...
Valinomycin is a dodecadepsipeptide, that is, it is made of twelve alternating amino acids and esters to form a macrocyclic molecule. The twelve carbonyl groups are essential for the binding of metal ions, and also for solvation in polar solvents.