PPS96 Assignment 2

These questions were set for the second assessed assignment in last year's course. They are short answer questions of approximately equivalent standard to the exam. They cover the whole syllabus - so don't worry if you can't answer them all just yet.

It would be very useful for you all to attempt these. They will not be assessed this time, but model answers will be released within a few weeks.

Some self-assessment quizzes should also be released over the next few weeks.

1. Define the term "chiral centre" as applied to amino acids. Which amino acids have chiral centres that are not alpha-carbon atoms? (Max. 5 points)

2. Where are the highest B factors to be found in a protein molecule in a crystal structure? Why? Are certain amino acids more likely to have high B factors than others?(Max. 7 points)

3. What are the commonest tertiary structures of proteins which consist of alternate helix / sheet along the protein chain?(Max. 4 points)

4. What is the Ca2+ ion binding motif associated with an E-F hand?(Max. 5 points)

5. Which residue causes an alpha-helix to kink or distort, and why?(Max. 2 points)

6. What types of symmetries are involved in protein quaternary structure?(Max. 5 1/2 points)

7. Which, in your opinion, is / are the most hydrophobic amino acid/s? Why?(Max. 6 points