Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
alpha helix
|
3.6 aa per turn
5.4 Å per turn no Gly or Pro psi is 0 to -70 degrees rich in Ala and Leu as they are small and fit into the hydrophobic inside large dipole moment |
|
|
beta sheet
|
psi between 90 and 180 degrees
parallel: weaker H bonds (6.5 Å) antiparallel: more direct/stronger H bonds (7 Å) |
|
|
type I turn
|
Pro is 2nd aa out of 4
carbonyl of 1st aa hydrogen bonds with nitrogen's hydrogen of the 4th aa 6% of Pro is in cis, most of which are in these beta turns |
|
|
type II turn
|
Gly is 3rd aa out of 4
1st aa's carbonyl hydrogen bonds with hydrogen on amine of 4th aa |
|
|
alpha-keratin
|
-- 2 right-handed alpha helices wrapped in parallel, forming a left-handed helix overall
-- 5.2Å per turn instead of the alpha helix 5.4Å -- hydrophobic interface -- rich in hydrophobic residues (Ala, Val, Leu, Ile, Met, Phe) -- disulfide bonds increase strength (rhino horn has 18% aa involved in disulfide bonds) |
|
|
Collagen
|
phi -51, psi 153
right-handed twist overall of 3 left-handed alpha chains rich in Gly, Ala, Pro, 4-Hyp Gly-X-Y X often Pro Y often 4-Hyp |
|
|
Silk fibroin (Beta keratin)
|
Beta sheets with hydrogen bonding and extensive van der Waals interactions between sheets
doesn't stretch because B conformation is already highly extended, but it is flexible because the van der Waals interactions can scoot over a few amino acids antiparallel beta sheets rich in Ala and Gly (often alternating), help stack the sheets tightly |
