Phosphorylation of the Ser-155 on \"Protein-A\" exposes the Lys-300 to the surfa
ID: 193177 • Letter: P
Question
Phosphorylation of the Ser-155 on "Protein-A" exposes the Lys-300 to the surface of Protein-A, which is followed by the destruction of Protein-A. Which of the following is most likely the case for the process? Step-1 Step-2 O The non-covalent interaction of the phosphate group targets the protein for degradation. The exposure of Lys-300 allows for binding of ubiquitin which targets the protein for degradation. The conformational change in step-2 renders the protein unstable causing it to degrade. O This is an example of a negative feedback loopExplanation / Answer
Answer: b. The exposure of Lys-300 allows for binding of ubiquitous which targets the protein for degradation.
The ubiquitin professional degradation involves utilizing 3 ubiquitin ligases that attach a ubiquitin modify to either kusum, serine or cysteine of substrate protein which is then engulfed by the proteasome for degradation.
Not (a) because joining of phosphate is a covalent interaction. Not (c) because exposure of a lysine residue is not a dramatic conformational change that could destabilize the entire protein. Not (d) because feedback loop comes into picture when the product is formed in excess which then goes and binds allosterically to one of the key enzymes involved in its synthesis.