Question

Autophosphorylation is done on

• A. His residues
• B. Ser/Thr residues
• C. Cys residues
• D. Lys residues

Hint:

Histidine kinase autophosphorylation is crucial in bacterial signaling and differs from the typical phosphorylation of Ser/Thr in eukaryotic kinases.

Answer 1

The Correct Option is A

Step 1: Understanding autophosphorylation.
Autophosphorylation refers to a process where a kinase enzyme catalyzes the transfer of a phosphate group to itself, typically on specific amino acid residues. In protein kinases, this often occurs on histidine (His) residues in certain types of kinases, such as those in bacterial systems.
Step 2: Analyzing the options.
(1) His residues: Correct — Histidine residues are commonly phosphorylated in autophosphorylation, particularly in histidine kinase proteins.
(2) Ser/Thr residues: This is incorrect. Serine and threonine residues are commonly phosphorylated in eukaryotic protein kinases, but not in autophosphorylation.
(3) Cys residues: This is incorrect. Cysteine residues do not typically participate in autophosphorylation.
(4) Lys residues: This is incorrect. Lysine residues are not typically involved in autophosphorylation.
Step 3: Conclusion.
The correct answer is (1) His residues, as autophosphorylation typically occurs on histidine residues in histidine kinases.