Which of the Following is a Commonly Used Mechanism for Anchoring

Question

Which of the following is a commonly used mechanism for anchoring a protein to a membrane?
A) attaching a fatty acid to a serine residue to form an ester
B) attaching a fatty acid to a methionine residue to form a thioester
C) attaching a farnesyl group to a cysteine residue to form a thioether
D) attaching a fatty acid to a glutamine residue to form an amide
E) none of the above

Accepted Answer

Attaching a farnesyl group to a cysteine residue to form a thioether is a commonly used mechanism for anchoring a protein to a membrane. This is called prenylation and is commonly used for membrane-bound proteins such as G-proteins. Option A and D are incorrect as attaching a fatty acid to a serine or glutamine residue will not provide enough stability for anchoring the protein to the membrane. Option B is incorrect as thioesters are not commonly used for membrane anchoring but are more involved in protein degradation. Option E is incorrect as there is a commonly used mechanism for anchoring proteins to the membrane.