Proteins Flashcards
protein function?
determining physical traits, behavior, and physiology
protein structure
amino acid chains connected by polypeptide bonds
Chemical structure of amino acids
Central Carbon
Amino group (NH2) base
Carboxyl group (COOH2) acid
Hydrogen atom- (H)
R-groups / side chains contain functional groups
Can participate in chemical reactions
Formation of peptide bonds
A peptide bond is a C-N covalent bond resulting from a condensation reaction (water is formed)
Primary structure
the sequence of amino acids
Each protein sequence is unique
A single aa change can radically alter protein function
Secondary structure
hydrogen bonds between carbonyl group of one aa and amino group of another
Electronegative oxygen and nitrogen atoms leave hydrogen atoms with partial positive charges.
α-helix twist
β-pleated sheet folding in on itself
Tertiary structure
Bending and folding into 3-dimensional shape of polypeptide
Results from interactions between residues causing the backbone to bend and fold
Bonds between sulfur atoms
Hydrophobic interactions
Hydrogen bonds
Ionic bonds
Quaternary
bonding of 2+ distinct polypeptide subunits
Dimers- proteins w 2 polypeptide units
Homodimers- 2 identical subunits
Heterodimers- non identical subunits
Tetramer- 4 polypeptide chains
Explain what prion diseases are and know the Kuru example
Prions are when proteins folding are altered. Misfolding is infectious and spreads throughout proteins
Kuru “laughing disease”
spread through eating brains of deceased
hydrogen bonding effect in folding
polar side chains and opposite partial charges
hydrophobic interactions in folding
water forces hydrophobic side chains together
Van Der Waals interactions in folding
weak electrical between hydrophobic side chains
covalent bonds in folding
between sulfhydryl groups disulfide bonds
ionic bonding in folding
between groups with full and opposing charges
dimers
proteins with 2 polypeptide units
