L1- Amino Acids Flashcards
Non-polar Amino Acids
9: Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine, Phenylalanine, Tryptophan, Proline
Sulfur containing Amino Acid
Methionine. ATG Start Codon; Cysteine- sulfhydryl group
Disulfide bonds between two cysteine residues are covalent and very strong-important for protein folding
Uncharged Polar Side Groups
6: Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine
-OH on side group
Serine, Threonine, Tyrosine
Can be used to attach sugar chains or phosphate groups
Negatively Charged Polar R Groups
Aspartate, Glutamate: Side chains contain -COOH
Positively Charged Polar R Groups
Lysine, Arginine, Histidine
Primary structure of proteins
linear sequence of amino acids
covalently linked by peptide bonds- VERY STRONG
Peptidase can break them
Carboxyl group binds with an amino group -> amide bond
n-terminal to the left
Sickle Cell Anemia
mutation that replaces glutamic acid by valine
mutated amino acid is now non polar
when there is low oxygen, the protein stiffens and sitarist and blocks the flow of blood
Secondary Structure of Proteins
local folding as a result of hydrogen bonds between backbone amino and carboxyl groups
a-helix secondary
extensive intra-chain hydrogen bonding
side chains extend outward
Ex: keratin
b-sheet secondary
strands parallel to one another
hydrogen bonding
Prion Diseases
misfolded helix or sheet
can be heritable or infectious
cause amyloid plaques
Tertiary Structure
packing of secondary structures
folding so the interior is non-polar and exterior is polar
Forms domains that can have individual functional elements
Quaternary Structure
- arrangement of multiple polypeptide subunits
- subunits are held together by nonequivalent interactions
Fibrous Proteins (scleroproteins)
long filamentous, like rods/wires i.e.. collagen
- have secondary structure
- water-insoluble
