cysteineAminosäureresten

Cysteine Aminosäureresten refers to the amino acid cysteine and its presence within a protein chain. Cysteine is a unique amino acid due to its thiol side chain (-SH group). This side chain is highly reactive and plays a crucial role in protein structure and function. The most significant feature of cysteine residues in proteins is their ability to form disulfide bonds (-S-S-). These covalent bonds occur when the thiol groups of two separate cysteine residues, or even two cysteines within the same polypeptide chain, are oxidized. Disulfide bonds are vital for stabilizing the three-dimensional conformation of many proteins, including antibodies, enzymes, and structural proteins like keratin. They contribute significantly to the protein's overall integrity and ability to perform its specific task.

Beyond disulfide bond formation, the thiol group of cysteine residues can also participate in other important biochemical reactions. It can act as a nucleophile in enzymatic catalysis, coordinating metal ions, or undergoing post-translational modifications such as S-methylation or S-acylation. These modifications can alter the protein's activity, localization, or interaction with other molecules. The presence and specific arrangement of cysteine aminosaäureresten within a protein sequence are therefore critical determinants of its biological properties. Researchers study cysteine residues to understand protein folding, stability, and mechanisms of action, and their role in various diseases.