The membrane thickness for all the transmembrane domains of a multipass transmembrane protein are almost the same (~30 A). But the number of aa's in each TM domain may necessarily not be the same.
In that case different domains would have to re-orient/tilt in order to adjust to the approximately similar membrane thickness. I have read papers in this context but do not understand the methodology completely?
Anyone can recommend suitable text.
Bacterial and eukaryotic bilayer have different hydrophobic core thickness, corresponding to about 25 Å and 35 Å, respectively. Each amino acid in an alpha helix will translate 1.5 Å. So when oriented perpendicular to the lipid bilayer plane an alpha helix needs about 17 or 23 residues to span the bacterial or eukaryotic bi;ayer, respectively. Typically transmembrane helices are titled relative to bilayer plane, meaning the transmembrane helix will be longer than these two values.
Probably you are already aware of this hypothesis from the early 1990s, but if not you might enjoy it: Bretscher and Munro (1993) Cholesterol and the Golgi Apparatus, Science 261: 1280-1281.
There is still interest and controversy in this subject especially as it applies to membrane rafts.
Thank You Sir, the paper was helpful. I will browse pubmed for more papers related to the above one.
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