PL5 - Proteins in 3D Flashcards
What are the three levels of protein structure?
Primary, secondary, and tertiary
What is the primary structure of a protein?
The order of amino acid residues
What is the secondary structure of a protein?
The coiling of parts of the chain into a helix or folding into a pleated sheet
What is the tertiary structure of a protein?
The folding of the secondary structure to create a specific 3D shape
How is the secondary structure of a protein held toegether?
Hydrogen bonds between the -NH groups on one peptide link and the C=O on another
What types of bond hold the tertiary structure together?
Intermolecular bonds, ionic bonds, and covalent bonds
Where do instantaneous-induced dipole bonds tend to form in the tertiary structure?
Between non-poar amino acids.
These tend to be found in the centre of proteins
Why do non-polar amino acids tend to be found near the centre of proteins?
So that the id-id bonds they make don’t interfere with the H-bonding with the surrounding water molecules
Where in the tertiary structure do hydrogen bonds tend to form?
Between polar side chains
What can happen to a protein is amino acids with polar side chains are situated on the outside of its 3D structure?
It can form H-bonds with the surrounding water molecules and thus dissolve
Where in the tertiary structure do ionic bonds form?
Between ionisable side chains
Give an example of a covalent bond that might form in a protein’s tertiary structure
Between oxidised -SH groups on neighbouring cysteine residues to form -S-S- links
What does the shape of the tertiary structure vary according to?
The function of the protein and what amino acids make it up/where they’re situated
What type of secondary structure are structural proteins mostly comprised of?
Helices
What type of secondary structure do globular proteins contain?
Both helices and pleated sheets
