Protein structure Flashcards
What is a primary protein structure
the number and sequence of amino acids held together by peptide bonds in a polypeptide chain
- essentially the sequence of a chain of amino acids
What is a secondary protein structure
alpha helix - spiral spring shape formed between CO and NH groups as amino acids start to spiral
When do secondary protein structures occur?
When the amino acids are linked by hydrogen bonds
What does the primary structure do?
It indicates the overall shape and function of the protein
What are the 2 types of secondary protein structure?
Alpha helix
beta sheet
What is the tertiary structure dependant on
the primary structure - i.e: which amino acids are where
What shape is the tertiary structure?
globular shape - polypeptide chain ends and folds extensively forming a precise, compact shape
OR long straight fibres - like collagen/ keratin
Which structure is collagen?
Tertiary
Which structure is a fibrous protein?
Tertiary
What 4 factors maintain a tertiary structure
Ionic bonds
Hydrogen bonds
Covalent bonds
Hydrophilic-hydrophobic interactions
What is a quaternary structure?
An interaction of subunits to form a larger molecule
- more than one polypeptide chain in a cluster (aggregation) held together by hydrogen and ionic bonds and hydrophobic-philic interactions
What holds together polypeptide chains in a quaternary structure? (3)
Ionic bonds
Hydrogen bonds
Hydrophilic/phobic interactions
What are fibrous proteins?
Polypeptides that form long chains running parallel to each other linked by disulphide cross ridges
What links polypeptides in fibrous proteins?
disulphide cross ridges
Which structure is globular shaped
Tertiary
