In quaternary structure denaturation, protein sub-units are dissociated and/or the spatial arrangement of protein subunits is disrupted.
Tertiary structure denaturation involves the disruption of:
Covalent interactions between amino acid side chains (such as disulfide bridges between cysteine groups)
Noncovalent dipole-dipole interactions between polar amino acid side chains (and the surrounding solvent)
Van der Waals (induced dipole) interactions between nonpolar amino acid side chains.
In secondary structure denaturation, proteins lose all regular repeating patterns such as alpha-helices and beta-pleated sheets, and adopt a random coil configuration.
Primary structure, such as the sequence of amino acids held together by covalent peptide bonds, is not disrupted by denaturation.
Loss of function
Most biological proteins lose their biological function when denatured. For example, enzymes lose their catalytic activity, because the substrates can no longer bind to the active site, and because amino acid residues involved in stabilizing substrates’ transition states are no longer positioned to be able to do so.
Reversibility and irreversibility
In many proteins (unlike egg whites), denaturation is reversible (the proteins can regain their native state when the denaturing influence is removed). This was important historically, as it led to the notion that all the information needed for proteins to assume their native state was encoded in the primary structure of the protein, and hence in the DNA that codes for the protein.
February 27th, 2010 at 10:37 pm
In quaternary structure denaturation, protein sub-units are dissociated and/or the spatial arrangement of protein subunits is disrupted.
Tertiary structure denaturation involves the disruption of:
Covalent interactions between amino acid side chains (such as disulfide bridges between cysteine groups)
Noncovalent dipole-dipole interactions between polar amino acid side chains (and the surrounding solvent)
Van der Waals (induced dipole) interactions between nonpolar amino acid side chains.
In secondary structure denaturation, proteins lose all regular repeating patterns such as alpha-helices and beta-pleated sheets, and adopt a random coil configuration.
Primary structure, such as the sequence of amino acids held together by covalent peptide bonds, is not disrupted by denaturation.
Loss of function
Most biological proteins lose their biological function when denatured. For example, enzymes lose their catalytic activity, because the substrates can no longer bind to the active site, and because amino acid residues involved in stabilizing substrates’ transition states are no longer positioned to be able to do so.
Reversibility and irreversibility
In many proteins (unlike egg whites), denaturation is reversible (the proteins can regain their native state when the denaturing influence is removed). This was important historically, as it led to the notion that all the information needed for proteins to assume their native state was encoded in the primary structure of the protein, and hence in the DNA that codes for the protein.
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