BIOLOGY
PROTEINS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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two cystine residues that are close to each other
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aspartate and glutamate residues that are close to each other
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two cysteine residues that are close to each other
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cysteine and cystine residues that are close to each other
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Detailed explanation-1: -The formation of disulfide bonds between cysteine residues occurs during the folding of many proteins that enter the secretory pathway. As the polypeptide chain collapses, cysteines brought into proximity can form covalent linkages during a process catalyzed by members of the protein disulfide isomerase family.
Detailed explanation-2: -A disulfide bond is a covalent bond between two sulfur atoms (–S–S–) formed by the coupling of two thiol (–SH) groups. Cysteine, one of 20 protein amino acids, has a –SH group in its side chain, and can easily be dimereized to cystine in aqueous solution by forming a disulfide bond.
Detailed explanation-3: -Introduction. Cysteine is unique among coded amino acids because it contains a reactive sulph-hydryl group. Therefore, two cysteine residues may form a cystine (disulfide link) between various parts of the same protein or between two separate polypeptide chains.
Detailed explanation-4: -Disulfide bonds are covalent bonds that are created between two sulfhydryl groups. A reaction between two cysteine residues’ sulfhydryl (SH) side chains results in the creation of disulfide bonds.
Detailed explanation-5: -The tertiary structure of the protein At this stage, proteins start solidifying their structure by additional bonds such as disulfide bonds between two cysteines. The most important feature of tertiary structures is the presence of conserved regions with similar functions known as functional domains.