Many transmembrane proteins are oligomeric, with several identical sub-units. Th
ID: 60715 • Letter: M
Question
Many transmembrane proteins are oligomeric, with several identical sub-units. The oligomers are usually found to have some form of Cn symmetry, rather than Dn or any higher order. Suggest a reason for this observation.
A) Symmetrical oligomeric complexes consist of two or more identical subunits, which explains specific transport functions and provide additional stability for the molecule
B) The subunits traversing the membrane usually need to present different domains to the two sides. No symmetry involving twofold axes parallel to the membrane surfaces should be expected.
C) Symmetrical oligomers are favored because of stability and finite control of assembly. Several functions limit symmetry, such as interaction with DNA or membranes, and directional motion.
Explanation / Answer
B) The subunits traversing the membrane usually need to present different domains to the two sides. No symmetry involving twofold axes parallel to the membrane surfaces should be expected.
Many transmembrane proteins are oligomeric, with several identical sub-units. The oligomers are usually found to have some form of Cn symmetry, rather than Dn or any higher order. This is because the subunits traversing the membrane usually need to present different domains to the two sides. No symmetry involving twofold axes parallel to the membrane surfaces should be expected.