Question

Answer the following questions please:

1) What factors contribute to tertiary structure stability? Give specific examples of the bonds involved, and which one is most important.

2) Define leucine zipper, helix-turn-helix, helix-loop-helix, and zinc finger, and explain why each is stable.

3) What is alpha-helix supercoiling, and why is it so favorable?

4) Why are quaternary structures so important to cell function?

5) Define the following domains: SH2, SH3, Bromo, Chromo, PTB, SNARE, EF-Hand?

Answer 1

1)

Chemical bonds & interaction that contribute in tertiary structure stability are-

1) Hydrogen bonding
2) ionic bonding
3) dipole-dipole interactions
4) London dispersion forces

All these four are non-covalent interaction.
These are primarily the interaction of the R group of amino acids with othet electronegative atoms present in protein structure.

5)hydrophobic interactions

In these bonds,amino acids with nonpolar, hydrophobic R groups cluster together on the inside of the protein, leaving hydrophilic amino acids on the outside to interact with surrounding water molecule

6)Disulfide bonds

There is covalent linkages between the sulfur-containing side chains of cysteines.

S-S is most strong bond among the above mentioned bonds.