DD - Protein Structure (3) Flashcards
What is protein modification and when does it occur?
- Covalent processing events that change the properties of a protein by proteolytic cleavage and adding a modifying group
- Occur during post translation
What are the 7 main types of modification?
- Glycans (Carbohydrates)
- Phosphates
- Palmitoylation (Lipids)
- Proteins (Ubiquitin)
- Methylation
- Acetylation
- Proteolytic maturation
What is glycosylation?
Addition of complex carbohydrate group
What does protein glycosylation control? (6 things)
- Cellular pathways
- Protein trafficking
- Cell adhesion
- Host-pathogen interaction
- Protein stability/folding
- Protection against proteases
What is phosphorylation? and what is it important for?
- A process in which a phosphate group is added to a molecule, such as a sugar or a protein
- Important in downstream signalling
What proteins add phosphate groups and which remove phosphate groups?
Kinases add phosphate groups
Phosphatases remove phosphate groups
What is palmitoylation?
Addition of long lipid groups (help anchor proteins in membrane)
What amino acids can palmitoylation occur?
Cysteine, Glycine and Lysine
What is ubiquitination and degradation?
Proteins are marked for degradation by the attachment of ubiquitin to the amino group of the side chain of a lysine residue
What is methylation?
Addition of a -CH3 group to a protein
Occurs in lysine
What is acetylation?
Addition of an acetyl group to an organic chemical compound
Occurs in lysine
What is proteolytic cleavage?
The process of breaking the peptide bonds between amino acids in proteins
What happens from
Pre-proinsulin –> Proinsulin –> Insulin
Pre-proinsulin –> Proinsulin
- Cleavage of signal peptide
- Oxidation of disulfide bridges
Proinsulin –> Insulin
- Cleavage of C-peptide
How are peptide bonds broken?
Broken by hydrolsis by boiling in 6M acid
Name the 4 main prosthetic groups?
- Haem
- Lipid
- Metal ion
- Nucleic acid
