Lecture 7 Flashcards
linear amino acid chain
primary structure
the alpha helix, beta-pleated sheet, or triple-helix formed by hydrogen bonding between peptide bonds along the chain
secondary structure
a protein folds into a compact, three-dimensional shape stabilized by interactions between R groups of amino acids
tertiary structquature
arrangement of multiple polypeptide chains (subunits)
quaternary structure
the release of water molecules from the structured solvation layer around the molecule as the protein folds increases the net entropy
hydrophobic effect
Interaction of N-H and C=O of the peptide bond leads to local regular structures such as alpha helices and beta sheets
hydrogen bonding
medium-range weak attraction between all atoms contributes significantly to the stability of the interior of the protein
London dispersion forces
long-range strong interactions between permanently charged groups
electrostatic interactions
tendency of a protein to maintain a native conformation
stability
highly structured shell of H2O around a hydrophobic molecule
solvation layer
Effects of resonance on peptide bonds
Causes them to 1. be less reactive compared with esters, 2. to be quite rigid and nearly planar, 3. to exhibit a large dipole moment in the favored trans configuration
Angle between peptide groups
torsional angle
angle around the alpha carbon-amide nitrogen bond
phi
angle around the alpha carbon-carbonyl carbon bond
psi
most common direction of alpha helices
right-handed
