Question

What secondary and/or tertiary structures are favored in the membrane core, and what weak interactions do they have in common?

Answer 1

Alpha-helix bundle and Beta-barrel are the two main structures of membrane proteins. The helix bundle is a complex long trans-membrane protein that packs several alpha-helixes; while beta-barrel protein has several beta-sheets rolled up, and it is shorter and less hydrophobic than the alpha helix bundle. the alpha helix is stabilized by hydrogen bonding in the helix backbone. The similarities between the helix bundle and beta-barrel is that, in order to fit the basic structure of lipid bilayer in membrane, they both contain hydrophobic amino acids in the middle of the protein, however, beta-barrels are considerably less hydrophobic than helix bundle.