Protein Structure and Function Flashcards
Biological functions of proteins
Structural
Movement
Enzymes
Transport
Membrane transport
Hormones
Receptors
Defence
Gene regulation
Chromosome separation
Which amino acid has the NH3 group?
First
N terminal end
Which amino acid has the COOH group?
Last
C terminal end
Glycosylation
Addition of sugar
Primary structure
Sequence of amino acids in protein chain
Secondary structure
Folding/coiling of peptide chain (alpha helix or beta pleated sheet)
Tertiary structure
Peptide chain folds upon itself
Quaternary structure
Folded peptide chains join
Alpha helix structure
H bonds in the same polypeptide chain
H bonds between peptide bond Carbonyl O and H of N-H every 4th peptide
R groups on the outside
Beta pleated sheet
Linear peptide chains
H bonding between peptide chains
Types of beta sheet structures
Antiparallel sheet
Parallel sheet
Collagen structure
3 chains
H bonds between chains
Features of an alpha helix protein
Globular
Compact together
Features of a beta sheet protein
High tensile strength
No elasticity
Forces that stabilise protein structure
Disulphide bridges
Hydrogen bonds
Electrostatic interactions
Van der Waals forces
Hydrophobic effect
Conditions that proteins are sensitive to
pH
Temperature
Ionic strength
Features of a peptide bond
Shorter than C-N bond
No rotation
Delta negative charge on Oxygen
Delta positive charge on Nitrogen
PKU
Cannot breakdown phenylalanine
Reduced Tyrosine production
Reduced hormones eg dopamine and melanin
Cause of albinism
Defective tyrosinase
Tyrosine cannot breakdown to form melanin
What amino acids can be glycosylated?
Asparagine
Serine
Threonine
Amino acids commonly found in alpha helices
Alanine
Aspartic acid
Glycine
Leucine
Lysine
Serine
