Exam 3: Proteins

The structural formulas for the 20 naturally occurring amino acid residues are shown in the panel below. Answer the following question(s) with the help of this panel. -Which of the amino acids shown above has the most limited combinations of phi (?) and psi (?) angles in its Ramachandran plot? Write down the one-letter abbreviation for it, e.g. A.

Switch proteins that bind and hydrolyze GTP are ubiquitous cell regulators in a wide variety of molecular processes. Which of the following statements is NOT true regarding these proteins?

Which of the regulatory interactions 1 to 5 depicted in the following diagram is NOT an example of a negative feedback regulation?

Some protein domains are found in many different proteins and have been especially mobile during evolution. A domain of this kind is called a "protein …"

For a simple enzymatic reaction that involves only one substrate and follows Michaelis-Menten kinetics, the changes in the concentrations of substrate, product, free enzyme, and the enzyme-substrate complex over the course of the reaction are depicted by solid curves in the graph below. Which curve (1 to 4) corresponds to [ES]? Write down the number as your answer.

Many macromolecular complexes in the cell contain scaffold proteins. What do these proteins do that benefits the cell?

An amino acid residue that is not part of the active site of an enzyme and does not interact with the ligand is nevertheless critical for ligand binding and is highly conserved. How can this be explained?

Which of the following is NOT the role of molecular chaperones in the folding of cellular proteins?

How do multienzyme complexes in the cell, such as the fatty acid synthase, enhance reaction rates?

The structural formulas for the 20 naturally occurring amino acid residues are shown in the panel below. Answer the following question(s) with the help of this panel. -What is the amino acid sequence of the peptide depicted below? Write down the sequence from the N- to the C-terminus, and use only the one-letter abbreviations, e.g. AGCNT.

Which of the following stretches of amino acid residues would you expect to find in the interior of protein molecules?

Phosphorylation of a protein by a protein kinase …