Question

Biochem- please answer all

You need to denature a heterodimeric protein that uses both ionic interactions and hydrophobic forces to hold the dimers together. Each subunit has 2 disulfide bonds that hold their 3 structures together. One subunit is primarily composed of P-Sheets while the other has multiple helix-strand-helix motifs. The subunit with the helix-strand-helix also has a number of polar and charged residues on its surface. What would you do to denature this protein and which NCI would be effected? (5 pts) 1. Explain the important conclusion from the Anfinsen experiment and its significance. Why was this work Nobel prize worthy? (4 pts) 1. 1. Why does it make sense that the first protein chaperones(Hsp70) discovered were expressed as a response to heat shock? (4 pts) 1. Develop analogies for the models of protein folding hydrophobic collapse, framework model and nucleation model. Make sure to explain your analogies. (3 pts for each model)

Answer 1

Answer 1)

Denaturation can occurs when protein and nucleic acid are subjected to elevated temperature or extreme of pH or applying some chemical like salt urea or other chemical reagents .An enzyme looses it's chemical activity when it is denatured .

The structure denaturation involves covalent interactions between amino acid side chain,noncovalent dipole dipole interaction between polar amino side chain .Vander Waals interaction 1) .Denaturation due to chemical reagents like DMSO urea ,propylene glycol ,formamide etc 2) denaturation due to air 3) Biological induce denaturation.etc

Answer 2)

In Anfinsen experiment RNA was denatured with urea and beta mercaptoethanol .The significant conclusion are

All the necessary information for protein folding is in the primary structure of RNA..The information required to specify the catalytically active three dimensional structure of ribonucleic is contained in its amino acid sequence i.e.primary structure determines protein conformation.

Answer 3

The firat protein Chaperones (Hsp.) Is known as heat shock because those protein assist in the repairs of denatured protein or pramod their degradation after stress or injury they have been referred to as molecular chaperons .It protect organism Frome subsequent severe stress.

Answer 4

1) Hydrophobic collapse _ it is the process of production of 3 _ D confirmation adopted by polypeptide in polar solvent .The polypeptide forms initial secondary structure (alpha helical and beta strands ) creating regions of hydrophobic residue.thise polypeptide interacts with water placing thermodynamic pressure on these regions which then aggregate or collapse in to tertiary structure .Significance . Those results in Parkinson's disease and Alzheimer's disease.

2) Framework model _ It is the sequence of protein folding event .In which the random coil or denatured form pardeshi through three stages 1)The formation of fluctuating embryos ,in which disconnected regions of second ary sructure are form. 2) collapse of this region in to and intermediate compact structure .3) hence The structure is formed .

3) nucleation model, _ In this method the surface of polymer is created and introduces surface energy parameter .