E1L1 - 3D Conformation of Proteins Flashcards
The “fold” refers to the arrangements of ________ structure elements that comprise a domain.
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
B. Secondary
T/F: Orthologs refer to two proteins of the same protein family, performing a similar function in THE SAME organism.
FALSE. Orthologs refers to two proteins of the same protein family, but in DIFFERENT organisms.
If two proteins have greater than 50% homology in primary structure and are related through evolution, they are said to be in the same:
A. Family
B. Fold
C. Superfamily
D. Super-fold
A. Family
Which of the following are NOT necessarily related by evolution?
A. Two proteins of the same family
B. Two structures in the same super-fold
C. Two orthologs
D. Two paralogs
B. Two structures in the same super-fold
What this expression represent:
Pitch / (# residues per turn, n)
Rise per residue.
Why does this matter?! This matters because H-bonds form in alpha-helixes only at very precise distances between residues!
Which of the following is an example of a “motif”, strictly speaking?
A. EF-Hand
B. Calmodulin
A. EF-Hand
note, 2 EF-Hand motifs make up a Calmodulin fold
Which of the following are examples (we saw in lecture) of proteins with multiple domains?
A. Protein C (coagulation pathway protease)
B. Hexokinase
C. All of the above
C.
Which protein needs features a glycine in every 3rd residue of the primary structure, to form a “glycine edge”?
Collagen
Which of the following are examples of derived amino acids?
A. Cysteine B. Cystine C. Selenocysteine D. Hydroxyproline E. Two of the above
E. Two of the above
Cystine and Hydroxyproline are examples of derived amino acids. That was the whole point, for example, of the Vitamin C discussion. We need VitC to make hydroxyproline!
Which of the following proteins, in the lecture, contain alpha-helixes that interact via apolar edges? A. Collagen B. Alpha-keratin C. Tropomyosin D. All of the above
D. All of the above!
In Dr. Scholtz’s view, cystine bonds constitute what order of protein structure?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
B. Secondary.
However, C. Tertiary is also defensible, since globular proteins such as Immunoglobulins are tied together using cystine bonds which are super tough, so to promote its survival in the harsh aqueous environments!
n = 3.6
Note: n = 3.0 residues per turn, for collagen
How many residues there are, per turn of an alpha - helix
T/F: All amino acids have rotation around their phi and psi bonds!
False: proline.
A given alpha-helix has 63 amino acids. How many turns are present?
63 / (7 amino acids per pair of turns) = 9 pairs of turns = 18 turns
