protein structure Flashcards
1
Q
4 levels of protein structure
A
- primary
- secondary
- tertiary
- quaternary
2
Q
features of primary structure
A
- order of amino acids in a poly peptide chain
- determined by mRNA
3
Q
Secondary structure features
A
- hydrogen bonds between peptide bonds of polypeptide chain
- form 3 types of structures :
alpha helix, beta sheets + triple helix
4
Q
3 forms of secondary protein structure
A
alpha helix, beta plated sheets and triple helix
5
Q
features of alpha helix
A
- right handed spiral
- r groups point outwards
- proline amino acid causes 90 degree change in direction
6
Q
features of beta plated sheets
A
- can be parallel/ antiparallel
- layers of polypeptide with R groups between sheets
7
Q
triple helix
A
3 strands spiralling around each other
8
Q
features of collagen
A
- triple helix
3 left handed strands form a right handed superhelix - individual strands = tropocollagen
- covalent bonds hold strands together
- water insoluble
- chains held together by covalent bonds
- determines the strength of a tissue
9
Q
Tertiary structure
A
- interactions between R groups of amino acids
- final 3d structure of protein
- hydrogen bonds, van der waals forces, di sulfide bridges, ion salt bridges
10
Q
formation of disulfide bonds
A
2 adjacent SH group is oxidised
- forms an S to S bond
- process is reversible
11
Q
location of non polar proteins
A
- found in protein core due to repulsion of water (protein in solution)
12
Q
chaperones + role in protein structure
A
- used to manipulate proteins into shape + move proteins to required location
13
Q
quaternary structure
A
- addition of poly peptide sub units
- prosthetic groups added (non protein components)
14
Q
2 types of proteins
A
- fibrous and globular
15
Q
features of globular proteins
A
- globular have hydrophobic protein cores + hydrophilic protein on outermost surface
tend to be spherical - soluble
16
Q
features of fibrous proteins
A
- insoluble, fibrous chain like proteins
17
Q
collagen repeating sequence
A
x, y, Gly
x= any protein
y = proline/ hydroxyproline
Gly = Glycine
