Ser/Thr Protein kinases

Question 1

Phosphorylation reaction

• which aa
• process

Answer 1

Serines, threonines, and tyrosines have hydroxyl groups that can be phosphorylated

Phosphorylation occurs by aa -OH nucleophilic attack on the gamma phosphate of ATP

Question 2

Protein kinase function

Answer 2

situates the aa residue and ATP molecule in proper position for phosphorylation. (usually to activate)

Question 3

types of secondary protein modification

Answer 3

1. protein phosphorylation
2. acetylation
3. glycosylaation
4. ubiquitination
5. proteolytic cleavage

Question 4

Structure of ATP molecule

Answer 4

1. ribose
2. purine base: adenosine
3. 3 phosphate groups

phosphate bonds of ATP are E rich and can donate to other molecules

Question 5

structure of Protein kinases

Answer 5

kinases consists of:
1 large and 1 small lobes
Cleft: where ATP and substrate binds
activation loop

Question 6

activation loop

Answer 6

highly conserved glycine rich loop at catalytic core

-plays role in altering the conformation of the enzyme: forces ATP into right position for phosphorylation reaction (GDP to GTP).

Question 7

True/False

in 70% of kinases, the activation loop must be phosphorylated in order to activate the kinase

Answer 7

True

Question 8

Closed conformation of glycine rich loop allows for what?

Answer 8

forces the gamma-phosphate of ATP into right position for phosphorylation

(fast rxn)

Question 9

Open conformation of glycine rich loop allows for what?

Answer 9

allows for exchange of generated ADP for a new ATP

slow rxn

Question 10

mTOR

Answer 10

a Ser/Thr Kinase

FYI: regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis, and transcription