Exam 4: Protein Structure

Cystic fibrosis results from the misfolding of proteins that never get the chance to properly insert into the membranes of lung epithelial cells and perform their function. This is generally referred to as a disease.

What do Ramachandran plots show?

Collagen is an important structural protein in biological systems. It is formed by a repeating unit containing glycine, proline, and 4-hydroxyproline (4HyP). The synthesis of 4HyP from proline requires vitamin C. Draw the structure of 4HyP.

Using the table below, determine the kind of gene mutation illustrated. ATG_AAT_CAC $\rightarrow$ ATG_AAG_CAC

Which statement regarding protein secondary structures is correct?

List reagents and conditions that denature proteins.

Use the table below to determine how many possible RNA sequences could code for the dipeptide Pro-Ala.

Draw the structure of the amino acid cysteine showing the predominant form found at pH = 12.0 (assume -NH₃⁺ pKa 9.0; Cys pK_R 8.0; -COOH pKa 2.0).

The peptide bond is stronger than the ester bond. What structural feature of the peptide bond gives it additional bond strength?

Which of the following statements about $\alpha$ -helices and $\beta$ -sheets are FALSE?

If the titration curve shown below is for the amino acid glycine, at which point in the curve is the pI?

The following amino acid is discovered in a newly isolated protein. What would it be called, and does it represent a new amino acid?

Which one of the following statements comparing alpha keratin and silk fibroin is true?

Protein tertiary structures

What is a difference between parallel and antiparallel $\beta$ -sheet secondary structures?

A polypeptide has a high pI value. Which amino acids might comprise it?

What specific reagents or conditions might be found on the X-axis label of the following figure?

Which of the following statements regarding protein domains is true?

The $\phi$ and $\Psi$ angles are the

How many different protein folds are recognized in the formal system of organization, referred to as SCOP: Structure Organization of Proteins?