Question

Compare and contrast the characteristic amino acid sequences that mediate correct targeting in periplasmic vs. integral membrane proteins.

Answer 1

Peripheral protein is only located in the inner or outer surface of the phospholipid bilayer like floating iceberg whereas integral protein is embedded in the whole bilayer. Integral proteins have hydrophobic and hydrophilic areas where as peripheral do not.

The stretch of the integral protein within the hydrophobic interior of the bilayer is also hydrophobic, made up of non-polar amino acids Like the lipid bilayer, the exposed ends of the integral protein are hydrophilic. When protein crosses the lipid bilayer it adopts an alpha-helical configuration.