BIOCHEMISTRY The sequence of keratin is different from that

BIOCHEMISTRY: The sequence of - keratin is different from that of - keratin.

a) What is the amino - acid repeat found in the - keratin sequence, and into what secondary structure does it fold?

b) DRAW the - keratin structure formed by a four amino - acid sequence, and pair it with the same sequence to form the overall stable structure of - keratin . How do the sidechains ( R - groups ) interact with one another to stabilize the overall structure ?

Solution

Beta-keratin is different from the alpha-keratin as it consists of stacked beta-pleated sheets whereas the alpha-keratins consist the alpha-helices. a) Beta - keratins are the hard protiens mainly found in reptiles and also in scales,feathers and claws of the birds which gives the rigidity to the structure. The amino acid repeat found in the beta - keratin sequences are mostly cystiene - glycine - proline - tyrosine. The beta-keratin folds into the beta - pleated sheets to form the secondary structure.