1. A Lys residue in a protein was changed to Asn, Asp, and Arg. Which substitution would have the greatest effect on the tertiary structure? The least effect? Explain your answer.

2. If amino acid X has pI=4.6, what is its charge in each of the following buffers?

A. pH=10.2

B. pH=7.4

C. pH=5

D. pH=2.5

3. Which of the amino acids below would most likely be found on the surface ofa protein? Which would be found on the inside of a globular protein? Explain your answer.

Asp, Phe, Ser, Leu, Arg