Disulfide bridges are sometimes called disulfide bonds or S-S bonds. They are covalent links between the Sulphur atoms of two cysteine amino acids and their formation stabilizes the tertiary and higher order structure of proteins. Disulfide bridges formed between cysteine residues in peptides and proteins are fundamental building blocks for the molecular architecture and, thus, can govern basic biological processes. The formation of a disulfide bond by two side chain Sγ atoms of spatially proximal cysteines constitutes a two-electron oxidation process leading from reduced sulfhydryl groups of cysteines (S-H) to the oxidized cystine (S-S) residue. In cellular environments, this reaction is often supported and accelerated by enzymes like thioredoxin or protein disulfide isomerases. Disulfide bridges can be formed intramolecular, in rarer cases even between two vicinal cysteines and constitute the only natural covalent link between polypeptides strands. In addition, they might occur as an intermolecular feature, sometimes leading to increased protein aggregation. Cleavage of disulfide bonds in biomolecules may result in the collapse of the native conformation and biological function. Here you can see how 3 disulfide bridges (ball-stick model) stabilize the structure of a snake venom toxin by connecting two parallel alpha helices (PDB code: 2OSH)
#molecularart ... #immolecular ... #disulfide ... #cysteine ... #bridge ... #stabilization .... #folding ... #venom ... #toxin ... #xray
Structure of the snake venom toxin rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #disulfide ... #cysteine ... #bridge ... #stabilization .... #folding ... #venom ... #toxin ... #xray
Structure of the snake venom toxin rendered with @proteinimaging and depicted with @corelphotopaint
