Protein structure Flashcards
What are the functions of proteins? [5 marks]
- Carrying
- Metabolism
- Cellular machinery (e.g. splicesomes, ribosomes)
- Structural scaffolding
- Sensing molecules
Structure of protein [4 marks]
- Tetrahedral
- Carboxyl and amine group attached to central carbon
- Variable side chain
- Hydrogen
Definition of a zwitterion [1 mark]
Compound with neutral charge, but which contains separate parts which are positively and negatively charged.
Laevorotatory amino acids [2 marks]
- remember CORN
- usual form of amino acids
Dextrorotatory amino acids [2 marks]
- remember NORC
- present in bacterial cell walls and therapy
What arrangement is the side chain R usually in? [1 mark]
Trans (alternating)
How are the polypeptides organised in antiparallel beta sheets? [1 mark]
They run in opposite directions
How are polypeptides organised in parallel beta sheets? [1 mark]
They follow the same direction
Alpha helix structure [2 marks]
- Right handed helix
- H bond between amino acids 4 residues apart
What is a cofactor? [1 mark]
Non-protein chemical compound or metallic ion that is required for an enzyme’s activity.
How are water soluble proteins usually arranged? [3 marks]
- Usually globular
- Hydrophilic residues outside
- Hydrophobic residues inside
What are the techniques used to determine protein structure? [4 marks]
- X-ray defraction crystallography
- Circular dichroism
- Cryoelectron microscopy
- Nuclear Magnetic Resonance
