Intro Flashcards
(36 cards)
Post translational modification of proteins
Where?
When?
Covalent addition/ cleavage of proteins
On amino acid chain/ terminal
After protein biosynthesis
3 germ layer types
Endoderm
Mesoderm
Ectoderm
How is pleuropotency established maintained and modulated ?
Cell signalling networks
PTM and proteome diversity extending function and stability
Reversible/ irreversible structure alteration
Types of PTM
Phosphorylation
Glycosylation
Methylation
Acetylation
Disulphide bond
Phosphorylation
+/- phosphate to ser/thre/tyr
Reversible
Conformational protein change
Enzyme activation/ deactivation
Glycosylation
Attaches sugar to N/O in an amino acid side chain cov linked via glycosidic
Methylation
+ methyl group at Lys/Arg residues
Acetylation
+ acetyl group to N-terminus of protein / lys res via coA
Donated by acetyl coA
Enzymatic / non-enzymatic > (de)acetylase
Co/post TM
Disulphide bond PTM
Cov links S atoms of 2 cys res
Cleavage PTM example
Translation/ translocation
Folding/ oxidation/ signal peptide cleavage
ER export/ Golgi transport/ vesicle packaging
Protease cleavage > C-peptide liberation
Carboxypepfidas E > mature insulin
Covalent addition PTM
+ new functional groups
Cell signalling and reaction enables
Response to environmental stress
Phosphate charge interaction
2 negative charges
(Enzyme activation)
Enzyme deactivation phosphorylation
Can mask binding site
Protein kinases
Enzymes catalysing phosphate transfer from a high energy donor
Unidirectional reaction
P from ATP
Phosphatase
Enzyme catalysing phosphate removal from substrate via hydrolysis of phosphoric acid monoesters > Phosphate ion + molecule w free hydroxyl
Glycosylation
Carb covalent binding to functional group on protein via glycosidic bond
Glycosylation function
Correct folding / protein stability/ cell adhesion/ immune response/ hormone activity/ embryonic development
Glycosylation location
On dolichol
5 Glycosylation types
O-linked (on ER/ Golgi)
N-linked (on ER)
Glypiation
C-linked
Phosphoglycosylation
Types of acetylation
N-terminal
Lysine
N-terminal acetylation
Co-trans in euk
Synthesis
localisation
Stability
Lysine acetylation
Txn factor linked
For gene expression / activation
L lysine >< acetyl-lysine
N-terminal acetyltransferases
Transfer from Ac-CoA to alpha amino group of 1st amino acid res
Specific to N-termini
Irreversible
Antagonistic acetylation
Acetylation removes + charge > wraps less tightly around histone > ^effector protein binding / txn ^ >txn hyperactivity
