Biology 2581B Study Guide - Quiz Guide: Peripheral Membrane Protein, Transmembrane Protein, Lipid-Anchored Protein
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1 Jun 2020
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Proteins in the cell must interact with many membranes. However, lipid membranes are hydrophobic, so, in order to associate, the parts of transmembrane proteins that cross the membrane must also be hydrophobic. Otherwise, the protein has to associate in a different way. There are a few different types of transmembrane proteins, classified by how they pass through the membrane: Single-pass proteins only cross the membrane once. Multipass proteins cross the membrane more than once. Both single-pass and multipass can have extracellular and intracellular domains. B-barrel proteins cross the membrane with no significant domains either side to create a pore. They act as a channel for molecules to pass through. Amphipathic helix proteins are those that have a helix embedded in the membrane due to its hydrophobic nature. We can work out if a protein is transmembrane by looking at the hydrophobicity of its amino acids.