b-Amyloid Ion Channels

Models of b-Amyloid Ion Channels in the Membrane Suggest That Channel Formation in the Bilayer Is a Dynamic Process: amyloid ion channel formation mechanism suggested (src)

Amyloid ion channels: oligomerization

results indicate that in lipid bilayers, a significantly higher percentage of these amyloids are oligomers (trimers and larger), while a small percentage of monomers and dimers are also present. On the contrary, soluble amyloid peptides are primarily monomers or dimers with a small percentage of higher-order oligomeric complexes. In the lipidic environment, thus, amyloid peptides undergo conformational changes favoring larger oligomeric complexes, although some large oligomeric complexes of soluble peptides can still retain their structure when inserted in a lipidic membrane (5, 23). A presence of large oligomeric complexes in membrane suggests that they could form supramolecular structures.


trimers are observed for amylin and Ab(1– 40), and tetramers are observed for ABri, amylin, Ab(1– 40), and a-synuclein

Also observed are pentamers for amylin and Ab(1– 40); hexamers for a-synuclein, SAA, ADan, amylin, and Ab(1– 40); and heptamers and octamers for a-synuclein and SAA.


Significantly, unlike earlier reports indicating amyloids’ tendency to form large fibrillar aggregates in solution, we confirmed that these peptides retained their globular structure over a period of several hours with no significant change in the size distributions and without significant aggregation, even at physiologically high concentrations.

multimeric peptide complexes have disk-like shapes with an outer diameter of 8–12 nm and often contain a central pore-like concavity with a diameter of 1–2 nm

Pentamers were mainly observed for amylin.

(src)