Some proteins have secondary, tertiary or primary structures. Even some of the nucleic acids have the same phenomenon. what is the importance of these structures in strength and flexibility? Which structure can tolerate heat or temperature?
Heating proteins causes them to become denatured, which means losing their higher order (secondary, tertiary, and quaternary) structure. The primary structure (linear sequence of amino acids) usually remains intact if the heating is applied at near-neutral pH because the amide bonds between amino acids are quite stable under those conditions.
Proteins can differ markedly in their sensitivities to heat denaturation. Some are stable at 100oC, whereas other denature at much lower temperatures. Highly thermostable proteins tend to be richer in stabilizing hydrogen bonds and salt bridges and have more compact structure than less thermostable proteins.
It is important to remember that higher-order protein structure is ultimately determined (mainly) by the primary structure, so the thermostability is also determined, ultimately, by the primary structure.
Heating double-stranded DNA causes it to denature, also. In this case, denaturation means separation of the two strands of the double helix. The thermostability of DNA is determined by the sequence of nucleotide bases. G-C base pairs have three hydrogen bonds, whereas A-T base pairs have only two. Therefore, the thermostability increases as the proportion of G-C base pairs increases.
Hi,
all proteins have a primary, secondary, tertiary and quaternary structure. The primary structure correspond to the sequence (amino acids or nucleic acids). It give you informations about your sample anb by performing some blast it is possible to know the family of your protein for example. Some small amino acids such as glycine can give flexiblity to your protein. The secondary structure give you informations about the conformation of each amino acid (helix, beta-strand, coil, ...). Most of the flexible residues are found in loop connecting helices/strands with helices/strands. The tertiary structure of a protein correspond to the 3D structure. It gives you some informations such as close proximity of secondary structures in space. From the 3D structure you can have access to the global fold of your sample, the active site and so on ... The quaternary structure give you some informations about the oligomeric state of your sample (monomeric, dimeric and so on ...).
Heating proteins causes them to become denatured, which means losing their higher order (secondary, tertiary, and quaternary) structure. The primary structure (linear sequence of amino acids) usually remains intact if the heating is applied at near-neutral pH because the amide bonds between amino acids are quite stable under those conditions.
Proteins can differ markedly in their sensitivities to heat denaturation. Some are stable at 100oC, whereas other denature at much lower temperatures. Highly thermostable proteins tend to be richer in stabilizing hydrogen bonds and salt bridges and have more compact structure than less thermostable proteins.
It is important to remember that higher-order protein structure is ultimately determined (mainly) by the primary structure, so the thermostability is also determined, ultimately, by the primary structure.
Heating double-stranded DNA causes it to denature, also. In this case, denaturation means separation of the two strands of the double helix. The thermostability of DNA is determined by the sequence of nucleotide bases. G-C base pairs have three hydrogen bonds, whereas A-T base pairs have only two. Therefore, the thermostability increases as the proportion of G-C base pairs increases.
Another thing in the case of proteins is that hydrophobic residues will be mainly located within the 3-d structure. This has to happen such that the protein molecules do not bind hydrophobically, which will lead to protein precipitation
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