Protein Structure and Function Flashcards
Where are the H bonds in an alpha helix?
In the same polypeptide (backbone, not side chains)
Is an alpha helix right or left handed?
Right
How many amino acids are there per turn in an alpha helix?
3.6
Explain the H bonding in a beta pleated sheet
Formed between peptide chains and hold strands together
What are the two types of beta pleated sheets? Which is more common in globular proteins/
Parallel and antiparallel. Antiparallel are more common.
What percentage of haemoglobin are alpha helixes?
60%
What is a super - secondary structure?
Combinations of alpha helixes and beta sheets
What happens to hydrophobic regions in proteins due to their inability to form H bonds?
The regions fold in a way to minis the contact with aqueous environment.
What are the 3 types of post - translational modifications to proteins?
- Glycosylation (addition of sugar)
- Phosphorylation (cell signalling and change in activity of enzymes)
- Methylation/acetylation of NH2 groups in side chains
What is the most abundant protein in vertebrates?
Collagen
What modified amino acids does collagen contain?
Hydroxyproline and hydroxlsyine
Glycine appears every 3 amino acids in collagen. Why is this important?
Only has a H as an R group which means that the proteins can pack closely together.
How many chains does collagen have? How many amino acids per turn? What type of helix is each chain?
3 and 3 and a left - handed helix
What do the 3 chains in collagen fold to make?
A right handed super helix
How many collagen types are there and what percentage of collagen does type 1 make up?
25 types and this makes up 90%
