Zinc keeps ‘two-faced cohort’ in check to prevent diabetes damagePublished On: Fri, Jul 1st, 2011 | Biochemistry | By BioNews
A new study led by an Indian professor has revealed that zinc keeps a protein called amylin in check and acts like a security guard in preventing major damage from diabetes.
Ayyalusamy Ramamoorthy, a professor of chemistry and biophysics at the University of Michigan, and his colleagues explained that in type two diabetes, amylin forms dense clumps that shut down insulin-producing cells, wreaking havoc on the control of blood sugar.
Amylin has been explained as something of a two-faced character. In healthy people who have normal levels of zinc in the insulin-producing islet cells of the pancreas, amylin actually pitches in to help with blood sugar regulation.
This is because in molecular terms, zinc prevents amylin also known as Islet Amyloid Polypeptide (IAPP) from forming harmful clumps similar to those found in Alzheimer”s, Parkinson”s, Huntington”s and various other degenerative diseases.
However, in a zinc-starved cellular environment of someone with type two diabetes, amylin has no watchful guard. It”s free to clump together with other amylin molecules in the molecular equivalent of a gang.
This clumping eventually leads to the formation of ribbon-like structures called fibrils, and because fibril formation has been linked to a number of human diseases, it was long assumed that fibrils themselves were toxic.
The study shows that the binding of zinc in the middle makes one end of the amylin molecule, called the N-terminus become more orderly.
“This is significant, because the N-terminus is very important in clump formation and amylin toxicity,” said Ramamoorthy.
The researchers also discovered that before amylin can begin forming fibrils, zinc must be rousted from its nesting place.
The study appears in the upcoming issue of the Journal of Molecular Biology.