Membrane proteins Flashcards
What is an integral membrane protein?
The protein is embedded in or crosses the plasma membrane
What is a peripheral membrane protein?
The protein is associated with the membrane but isn’t in it
How do you differentiate between an integral and peripheral membrane protein when doing an experiment with cells?
How hard are they to get out of the membrane. Peripheral will fall off but integral needs detergent
What is a monotopic protein?
The protein sticks out on one side of the membrane
What is a polytopic protein?
The protein sticks out on both sides of the membrane
What type of structures will make up a transmembrane domain?
Alpha helix or beta barrel. No beta turns
What is topology?
The localization of the protein domains relative to the lipid bilayer
What is a porin?
A type of beta barrel that is amphipathic and forms a polar hole in the membrane
What type of beta sheet makes up a beta barrel?
Antiparallel
How are porins specific for certain solutes?
The loops outside the membrane act as a filter and only lets one through
Can we predict if a protein will have a transmembrane domain?
An alpha helix can be predicted with a hydropathy plot, since there would be a long stretch of hydrophobic amino acids. Beta barrels have no distinct sequences and are a mix of polar and non-polar amino acids, so they are hard to predict
What is an amphitropic protein?
Proteins that are transiently associated with the membrane
