A group of membrane proteins can be extracted from membranes only by using detergents.All the proteins in this group have a similar amino acid sequence at their C-terminus: -KKKKKXXC (where K stands for lysine, X stands for any amino acid, and C stands for cysteine).This sequence is essential for their attachment to the membrane.What is the most likely way in which the C-terminal sequence attaches these proteins to the membrane?

Question

Quizplus · Accepted Answer

The presence of the cysteine residue in the C-terminal sequence suggests that it may be involved in covalent attachment to a membrane lipid via a thioester bond, which is common in membrane protein anchoring. The positively charged lysine residues may also interact with negatively charged head groups of membrane lipids, further stabilizing the protein-membrane interaction. The hydrophobic nature of the amino acids in the sequence also suggests that they may be involved in anchoring the protein in the hydrophobic region of the membrane. The fact that detergents are required to extract these proteins from the membrane further supports their association with the hydrophobic environment of the membrane.

A Group of Membrane Proteins Can Be Extracted from Membranes