Protein Structure and Function Flashcards
Properties of Alanine (Ala)
Aliphatic R group
Hydrophobic R group
Participates in hydrophobic interactions
Properties of Valine (Val)
Aliphatic R group
Highly hydrophobic R group
Participates in hydrophobic interactions
Properties of Leucine (Leu)
Aliphatic R group
Highly hydrophobic R group
Participates in hydrophobic reactions
Properties of Isoleucine (Ile)
Aliphatic R group Highly hydrophobic R group Participates in hydrophobic reactions Similar to leucine but has a different branching point Has 2 chiral carbons
Properties of Phenylalanine (Phe)
Aromatic R group
Abs UV light at 280 nm
Highly hydrophobic R group
Participates in hydrophobic interactions
Properties of Tryptophan (Trp)
Aromatic R group Heterocyclic Abs UV light at 280 nm Hydrophobic, bulky Participates in hydrophobic interactions Forms H bonds - donor
Properties of Methionine (Met)
Hydrophobic
Participates in hydrophobic interactions
Sulfer containing side group (thioether)
Forms H bonds - acceptor
Properties of Proline (Pro)
Aliphatic side chain with a distinctive cyclic structure
Weakly hydrophobic
Participates in hydrophobic interactions
Properties of Glycine (Gly)
Achiral
Weakly polar
Very small and flexible
Properties of Serine (Ser)
Polar, uncharged
H donor
can be phosphorylated
Properties of Threonine (Thr)
Polar, uncharged
H bond donor
can be phosphorylated
Properties of Tyrosine (Tyr)
Weakly polar, uncharged Aromatic R group Can participate in hydrophobic interactions H bond donor can be phosphorylated
Properties of Cysteine (Cys)
Polar, uncharged
Sulfer side group (sulfhydryl)
Can form H bonds
Forms disulphide bridges with other cysteines
Properties of Asparagine (Asn)
Amide side chain
Polar, uncharged
H bond donor and acceptor
Properties of Glutamine (Gln)
Amide side chain
Polar, uncharged
H bond donor and acceptor
Properties of Histidine (His)
Can be acidic or basic at neutral pH
Aromatic
Polar, charged/uncharged
Proton donor or acceptor
Properties of Aspartate (Asp)
Negatively charged R group at neutral pH Acidic amino acid Very polar H bond acceptor Called aspartic acid at pH 1
Properties of Glutamate (Glu)
Negatively charged R group at neutral pH Acidic amino acid Very polar H bond acceptor Called glutamic acid at pH 1
Properties of Lysine (Lys)
Positively charged R group at neutral pH
Basic amino acid
H bond donor
Very polar
Properties of Arginine (Arg)
Positively charged R group at neutral pH Guano group Basic amino acid Never deprotonated under physiological conditions Very polar H bond donor
Primary level of protein structure
Sequence of amino acids joined by peptide bonds
Secondary level of protein structure
Local folding of the polypeptide backbone into sub-structures
Tertiary level of protein structure
Arrangement of all atoms and sub-structures of a single, folded polypeptide in space
Quaternary level of protein structure
Association of two or more distinct folded polypeptides
