Which is the most stable structure of protein?

The a helix or b sheets are a most stable arrangement of H-bonds in the chain(s). These regions of ordered secondary structure in a polypeptide can be separated by varying lengths of less structured peptide called random coils.

How do nonpolar side chains affect protein structure?

As a polypeptide folds into its correct shape, amino acids with nonpolar side chains usually cluster at the core of the protein, staying away from water. Once the nonpolar amino acids have formed the nonpolar core of the protein, weak van der Waals forces stabilize the protein.

What is the problem of protein folding?

The protein folding problem is the question of how a protein’s amino acid sequence dictates its three-dimensional atomic structure. The notion of a folding “problem” first emerged around 1960, with the appearance of the first atomic-resolution protein structures.

Do proteins fold in nonpolar solvent?

The folded state is stabilized mainly by the burial and tight packing of over 80\% of the peptide groups and non-polar side chains. Our analysis suggests that proteins will be unstable in most polar solvents such as ethanol, extremely stable in non-polar solvents such as cyclohexane, and even more stable in a vacuum.

What stabilizes protein structure?

Hydrogen bonding in the polypeptide chain and between amino acid “R” groups helps to stabilize protein structure by holding the protein in the shape established by the hydrophobic interactions. Interactions called van der Waals forces also assist in the stabilization of protein structure.

Which structure of protein is more stable and why?

The overall three-dimensional shape of a protein molecule is the tertiary structure. The protein molecule will bend and twist in such a way as to achieve maximum stability or lowest energy state.

What is non-polar side chain?

Non-Polar Side Chains: Side chains which have pure hydrocarbon alkyl groups (alkane branches) or aromatic (benzene rings) are non-polar. Examples include valine, alanine, leucine, isoleucine, phenylalanine. This effect makes valine more non-polar than alanine; leucine is more non-polar than valine.

What stabilizes the tertiary structure of a protein?

The tertiary structure of a protein refers to the overall three-dimensional arrangement of its polypeptide chain in space. It is generally stabilized by outside polar hydrophilic hydrogen and ionic bond interactions, and internal hydrophobic interactions between nonpolar amino acid side chains (Fig.

Which of the following diseases is based on abnormal protein folding?

Protein misfolding is believed to be the primary cause of Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, Creutzfeldt-Jakob disease, cystic fibrosis, Gaucher’s disease and many other degenerative and neurodegenerative disorders.

Does protein folding decrease entropy?

An unfolded protein has high configurational entropy but also high enthalpy because it has few stabilizing interactions. A folded protein has far less entropy, but also far less enthalpy.

Are proteins polar or nonpolar?

Since proteins have nonpolar side chains their reaction in a watery environment is similar to that of oil in water. The nonpolar side chains are pushed to the interior of the protein allowing them to avoid water molecule and giving the protein a globular shape.

Are proteins soluble in non-polar solvents?

Proteins carry out the most difficult tasks in living cells. Our solubility studies suggest that protein solubility will be markedly lower in polar solvents such as ethanol and that proteins will be essentially insoluble in non-polar solvents such as cyclohexane.