Protein Structure

unique amino acid sequence

Function of protein determined by external chem and by shape

20 different R groups result in different properties ( hydrophobic, polar,, charge)

Non polar hydrophobic AA in the centre of the folded protein

Polar AA on the outside

Peptide bond is planar (stable covalent bond). H bonding too

50+ amino acids classes as polypeptide

3.6 amino acids per 360 degree turn (alpha helix)

R groups point outwards

3-4 amino acids stabilised by h bonding between peptide horde

(B sheet) forms flat sheet surface with stands of protein alongside

Stabilised by hydrogen bonds between amide links

Strands can be parallel or anti parallel

B sheets can stacked to form a 3D structure

Tertiary structure is the 3D folding of the protein. Determined primarily by the primary stfcutufr and also determined by the R groups of the amino acids

Collagen is triple helix with large number of prolines

StRggeeing of the 3 chains helps hydrogen bonding between chains

Collagen is major structural protein, it strengthens the tendons and and supports skin and internal organs.

Bones and teeth made by adding mineral crystals to collagen

Protein names and domains include globular, fibrous and domains

There’s a foldin problem. Misfolded prtoejsn may expose hydrophobic residues and form toxic species.

Molecular chaperones assist with folding and sometimes unfolding

Chaperones use ATP to provide energy to the folding process. They sometimes bind to hydrophobic amino acids and prevent hydrophobic effect driven folding. Some prevent the folded protein from unfolding.

Phosphpruksye occurs on ser threonine and tyrosine residues

Disulphide bond formation: covalent links between cysteine residues. Stabilise 3D structures

ubiquitination is when small protein is added to another, acts as signs, for cell destruction

Deamination is when amine group is removed