tertiary structure of proteins Flashcards
tertiary structure
the overall folding pattern of the whole polypeptide chain
simplest possible structure of tertiary protein
continuous secondary structure
globular vs fibrous
- Fibrous proteins are structural in nature, help maintain cell shape
- globular proteins are functional, carry out a specific biological function in the body
hydrophobic effect
the major driving force in protein folding
Where are non-polar and polar amino acids found in a protein
Non-polar: found near core away from exterior H2O
Polar: found on outer layer to make H-bonds with H2O or ions in solution
Good fit of amino acids
- side chains interlock to maximize close contact
- close contacts attract by weak van Der Waals forces
tertiary patterns of proteins
- consisting of mostly alpha-helical segments
- consisting of mostly beta-strand segments
- alternating alpha-helix and beta-strand segments
alpha-helix bundle
-consists of mostly AAs that prefer alpha-helix
- small clusters of breakers set the limits of each helix
beta-barrel
majority of AAs are beta preferring
- antiparallel B-sheet is more stable and side chains project out - odd on one side even on the other
- sheet is polar on one side non polar on the other
- large sheet (6-8 strands) wraps to form antiparallel B-barrel
alpha-beta barrel
- formed from parallel B-sheet and alpha-helix
- parallel B-sheets are less stable so must be on interior of protein meaning helixes are on exterior
- all helices lie on one side and sheet wraps to form parallel aB-barrel
- B-sheet forms central barrel surrounded by connecting a-helices
alpha-beta sandwich
- helices lie on both sides of the sheet give the parallel aB-sandwich
- sandwich filling is non-polar B-sheet between 2 layers of a-helix
- B-sheet is twisted for better packing
domains
sections of larger proteins that may adopt a different folding pattern
