Chapter 4 - Protein Structure Flashcards
Primary 1
Amino acid sequence
Secondary 2
Repetitive arrangement of local polypeptide chain regions
Tertiary 3
Spatial location of atom in a polypeptide chain
Quaternary 4
Protein complex of several polypeptide chains
Homodimer
Contains two identical protein subunits
Heterodimer
Contains subunits from different gene products
Peptides
Amino acid chain, formed by condensation bonds
Protein structure/function determined by …
Primary amino acid sequence
Four Helix Bundle
Most common formation, standard helix formation
Greek Key Fold
Four+ B-strands linked together to make a B-sheet
Rossmann Fold
Alternating a-helices and B-strands
TIM Barrel Fold
a/B barrel, large number of metabolic enzymes
Protein Folding Condition 1
Free energy difference between native and denatured must be favorable (G<0)
Protein Folding Condition 2
Entropy changes contribute to the folding process
Protein Folding Condition 3
Equilibrium shifts toward the folded state for proteins under favorable conditions of cellular movement
Apolipoproteins
Lipid transport particle components that carry cholesterol/triacylglycerol from the liver to other tissues
Protein Fold
Secondary structures that describe spatial arrangement of polypeptide chains
Immunoglobulin
Quaternary protein complex linked by disulfide bonds, antibodies
Ribonuclease A
Enzymes that cleave RNA
Prion Protein
Misfolded and leads to protein aggregation in the brain
Isoelectric Point
pH at which a given amino acid has no net charge
Zwitterion
Electrically neutral but dipolar molecule that contains positive and negative charge
Disulfide Bond
Covalent cross-link between two cytosine residues that stabilizes three-dimensional protein structure
Protease
Enzyme that catalyzes the hydrolysis of a peptide bond
