Search results
Results from the WOW.Com Content Network
A real polymer is not freely-jointed. A -C-C- single bond has a fixed tetrahedral angle of 109.5 degrees. The value of L is well-defined for, say, a fully extended polyethylene or nylon, but it is less than N x l because of the zig-zag backbone. There is, however, free rotation about many chain bonds. The model above can be enhanced.
In polymer science, the Lifson–Roig model [1] is a helix-coil transition model applied to the alpha helix-random coil transition of polypeptides; [2] it is a refinement of the Zimm–Bragg model that recognizes that a polypeptide alpha helix is only stabilized by a hydrogen bond only once three consecutive residues have adopted the helical conformation.
Depicted above is the monomeric ELP unit. X represents an arbitrary amino acid. Polymers are formed from this pentapeptide monomeric unite. Elastin-like polypeptides (ELPs) are synthetic biopolymers with potential applications in the fields of cancer therapy, tissue scaffolding, metal recovery, and protein purification.
Polymer nomenclature is generally based upon the type of monomer residues comprising the polymer. A polymer which contains only a single type of repeat unit is known as a homopolymer, while a polymer containing two or more types of repeat units is known as a copolymer. [22] A terpolymer is a copolymer which contains three types of repeat units ...
More specifically, polypeptides like collagen and silk, are biocompatible materials that are being used in ground-breaking research, as these are inexpensive and easily attainable materials. Gelatin polymer is often used on dressing wounds where it acts as an adhesive.
Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet. A β-strand is a stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation .
In general, polypeptides are unbranched polymers, so their primary structure can often be specified by the sequence of amino acids along their backbone. However, proteins can become cross-linked, most commonly by disulfide bonds , and the primary structure also requires specifying the cross-linking atoms, e.g., specifying the cysteines involved ...
Tacticity (from Greek: τακτικός, romanized: taktikos, "relating to arrangement or order") is the relative stereochemistry of adjacent chiral centers within a macromolecule.