Protein structure Flashcards
What is the primary structure
Covalently linked sequences of AA from the N- to C- terminus
What is secondary structure
Formation of substructures from H bonding between AA in the same polypeptide chain
Describe the alpha-helix strcture
Coiled rod of AA - Carbonyl will H bond with an amide 4 residues away
Describe the beta pleated sheet structure
H bonding between carbonyl and amide in different polypeptide chains
Distinguish the 2 types of beta pleated sheets
Anti-parallel - 1:1 pairing of AA
Parallel - 1:2 pairing of AA
Describe the reverse-turn structure
Carbonyl group is H bonded to an amide group 3 AA away
What determines secondary structure
Distribution of the 20 AA
What is tertiary structure
Arrangement and position of a polypeptide in space
What are the 3 structures making up a globular protein
Hydrophobic core
Hydrophilic exterior
Hydration shell
What is the isoelectric point
The pH where the net surface charge is 0
Which AA are primarily found in the hydrophobic core
9 hydrophobic amino acids
What is the hydrophobic effect
The idea that there are higher energy level bonds between water molecules rather than between water molecules and AA found on protein surface - unfavourable dissolution of AAs in water - So AAs in the core are brought together
What is the most abundant interaction within the hydrophobic core
VDW
What is quaternary structure
Association of 2 or more polypeptide sub-units
