Flashcards
Lectures 1-3: Protein Basics
Cards in this deck (28)
- 1General structure of an amino acidCentral carbon
Hydrogen
Alpha-carboxyl group
Alpha-amino group
R side chain (varies) - 2L and D formsL- amino group on the left
D- amino group on the right - 3Non-polar amino acids (carbon only)Glycine-H
Alanine-CH3
Valine-C3H7
Leucine-C4H9
Isoleucine-C4H9 (isomer) - 4Non-polar amino acids (others)Cysteine- C2H3S
Phenylalanine- CH2, ring
Tryptophan- 2C,NH, ring
Methionine- C3H7S
Proline- side chain attaches to amino - 5Uncharged polar amino acidsSerine-CH2OH
Threonine-like another a.a without NH2
Tyrosine-CH2, ring, OH
Asparagine- CH2, O NH2
Glutamine- as above with extra CH2 - 6Acidic polar amino acidsAspartic acid- CH2, COO
Glutamic acid- CH2,CH2, COO - 7Basic polar amino acidsLysine- C4H8,NH3+
Arginine-C3H6,N3H5
Histidine-complicated ring thing - 8pIThe pH at which the protein has a net charge of zero
- 9pKaThe pH at which 50% of the groups are ionised
- 10Amino acids with ionisable side chainsAsparagine
Glutamine
Histidine
Cysteine
Tyrosine
Lysine
Arginine - 11The peptide bondC-N peptide linkage
Partial double bond character
Planar
Often in cis (except after proline) - 12Primary structureThe order in which amino acids are linked via peptide bonds. Also, determines all the higher levels of structure.
- 13Secondary structureLocal regular folding stabilised by hydrogen bonds between backbone peptide groups
- 14Tertiary structureThe three-dimensional arrangement of all the atoms in the protein
- 15Quaternary structureThe way in which several polypeptide chains associate in a multi-subunit protein. Not all proteins have a quaternary structure
- 16A-helixHave 3.6 residues per turn
Have a ptich of 5.4A nm
Hydrogen bonding between carbonyl n and amide n+4
Side chains point out from helix - 17Amino acid(s) not present in a-helixGlycine-too flexible
Proline-cannot form hydrogen bond due to its cyclic structure - 18B-sheetCan be parallel or anti-parallel
Hydrogen bonds form between layers
Has pleated structure with side chains pointing up and down - 19Amino acid(s) not present in B-sheetProline- cannot form hydrogen bonds due to cyclic structure, also too bulky
- 20TurnsOften found in between anti-parallel B-strands
Made up of 4 amino acids, the second of which is often proline - 21Tertiary structure bondsHydrophobic interactions
ELectrostatic interactions
covalent disulfide bonds
hydrogen bonds
ionic bonds - 22DomainA relatively stable independently folded region within the tertiary structure of a globular protein
- 23Protein folding is driven byhydrophobic forces, and it is therefore the internal residues that drive the direct folding to native conformation
- 24NucleationThe formation of a-helix and b-sheet structures early in the folding process
- 25Factors that denature proteinspH
Heat
Detergents
Organic solvents
Some chemicals (e.g. urea) - 26Christian Anfisen's experimentRealised that denatured proteins could be renatured even when reagants were removed
- 27ChaperoneSmall protein that helps a protein to fold without the use of ATP
- 28ChaperoninLarge, multi-subunit protein that helps a protein to fold with the help of ATP
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- 100 level BIOC192 (Proteins) Flashcards on Lectures 1-3: Protein Basics, created by Becky Payne on 09/10/2016.
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- Becky Payne
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