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
Give examples of some structural proteins
Those in muscles and hair
Give some examples of globular proteins
Hormones and enzymes
