Theme 3

In a protein, the most conformationally restricted amino acid is ______; the least conformationally restricted is

Which one of these characteristics is not true for the  helix?

Which of these characteristics does not describe the  sheet?

Which statement below does not describe fibrous proteins?

Which of the following changes would not alter the functional characteristics of α keratin?

Which of the following statements is true regarding collagen?

Which of the following gives the best example of a nonrepetitive structure in a protein?

In the absence of ascorbic acid, prolyl oxidase is unable to oxidize proline residues in collagen to hydroxyproline, resulting in:

Of the following, which amino acid is most likely to be found in position 1 or 4 on α keratin?

Which of the following amino acids combinations have side chains with groups that have the greatest ability to stabilize the tertiary structure of a protein?

The low pH found in the gut can enhance the digestibility of dietary protein by causing

Which of the following occurs first when folding a disordered polypeptide chain into a stable protein formation?

Imagine that a researcher treated a protein with a high concentration of a chaotropic agent. Which of the following is the most likely result of the treatment? I. Nonpolar portions of the protein become more soluble. II. The protein begins to denature , III. The protein stability increases due to hydrophobic collapse

For B-sheets, the terms ‘parallel’ and ‘antiparalllel’ refer to ___________.

In general molecular chaperone proteins function by

When comparing similarities among multiple protein structures, which of the following is false?

The structure and sequence of a protein of unknown function was examined. Which of the following provides the best prediction of the protein's function?

Noncovalent forces that stabilize protein structure include all of the following except

The classic experiment demonstrating that reduced and denatured RNase A could refold into the native form demonstrates that:

The first step in the folding of disordered polypeptides into ordered functional protein is the formation of ______.

Evolutionary processes have

Chaperonins such as the GroEL/ES system

Protein diseases can be caused by which of the following

Which of the following would be most stable based on the information you have learned about protein structure?

Hydrogen bonds and maximum separation of amino acid side chains make the _____very stable and energetically ______________.

A chaperonin

A helix has hydrogen bonds between the carbonyl group from residue “n” and the amino group of residue “n+6,” which of the following is TRUE?

Which of the following contribute to the minimization of energy that occurs with protein folding?

Which of the following best describes the cause of Creutzfeld-Jakob Disease (a disease which human can develop with symptoms similar to those of mad cow disease)?

Proteins can denature due to a change in

48. Examine the three sequences below for collagen-like proteins. If hydrogen bonding were the most important feature in determining strength in fibrous proteins, which of the following sequences likely has the highest melting temperature and why? (Note: Flp = fluoroproline; Hyp = hydroxyproline) I. Pro-Hyp-Gly-Pro-Hyp-Gly-Pro-Hyp-Gly II. Pro-Flp-Gly-Pro-Flp-Gly-Pro-Flp-Gly III. Gly-Pro-Thr-Gly-Pro-Thr-Gly-Pro-Thr

Based on what you know about fibrous protein structure and sequence, what type of fibrous protein is this sequence most likely to from (You can assume that the protein is longer than what is shown and is repeating as shown, also note the polarity of each amino acid.)? Val – Cys – Lys – Val - Cys – Ala – Cys - Val – Cys – Lys – Val - Cys – Ala – Cys

Which of the following structural proteins has the greatest elasticity?

Noncovalent interactions account for the strength of which of the following structural proteins?

When considering fibrous proteins, which of the following statements is TRUE?

Which of the characteristics of collagen structure listed below contrubute to the tensi le strength of collagen? I. Collagen is made up of a triplet helix where 3 left-handed helices twist together in a right handed sense. II. Collagen includes at repeating sequence of amino acids with glycine every 3 amino acids in a helix with about 3 amino acids per turn. III. The three left-handed helices are staggered to allow close packing between glycine residues and rigidity from the bulky and inflexible proline/hydroxyproline.

Molecular chaperones bind to unfolded or partially folded polypeptide chains in order to accomplish which of the following?

What observation about protein refolding or renaturation helped to solidify the connection between primary amino acid sequence and 3-D structure?

Native protein purifications often require multiple reaction steps in order to purify the protein of interest from other proteins. One method used for protein separation in purification procedures is a change from water to an organic solvent. Which of the following would be accomplished by this solvent change?

When solving a protein structure using X-ray crystallography, the crystallographer generates a 3-D grid called an electron density map based on the observed diffraction pattern. The higher the resolution, the more detailed the electron density map and therefore the easier it is to identify what atoms (and therefore what amino acids) are in a given position. Based on the three choices below, in which of the following groups could the two of amino acids be the easiest to differentiate regardless of resolution? I. Leucine vs. Isoleucine II. Phenylalanine vs. Alanine III. Glutamate vs. Glutamic acid

The most important contribution to the stability of a protein’s conformation appears to be the:

In an aqueous solution, protein conformation is determined by two major factors. One is the formation of the maximum number of hydrogen bonds. The other is the:

In an alpha-helix, the R groups on the amino acid residues:

The major reason that antiparallel beta-stranded protein structures are more stable than parallel beta-stranded structures is that the latter:

The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence. This relationship is in contrast to secondary structure, where the amino acid residues are:

Proteins often have regions that show specific, coherent patterns of folding or function. These regions are called:

An average protein will not be denatured by

Which of the following is least likely to result in protein denaturation?

Protein S will fold into its native conformation only when protein Q is also present in the solution. However, protein Q can fold into its native conformation without protein S. Protein Q, therefore, may function as a ____________ for protein S.

Which of the following is not known to be involved in the process of assisted folding of proteins?