If proteins have an overall charge, how do membrane proteins traverse through the hydrophobic region of the plasma membrane?

Question

These two concepts seem almost contradictory, proteins have a net negative charge due to the amino acids in them each having a small negative charge, yet membrane proteins are able to exist traversing the plasma membrane, which is impermeable to charged molecules (hence the need for membrane proteins).How do these two statements remain true simultaneously?

Answer 1

The proteins may have a net charge but what allows this phenomenon to take place is the structure of the protein. As you may know, membrane proteins are comprised of amino acids that are either hydrophobic or hydrophilic. In a plasma membrane, the membrane protein has a structure where its hydrophobic amino acids are pointed outward toward the hydrophobic tails of the membrane, which encompasses a hydrophilic region of the protein that allows charged molecules to transverse the plasma membrane.