-
COO-
l
H3N - C - H
l
CH3
- Alanine (Ala)
- Apliphatic R group
- Hydrophobic R group
- Participates in hydrophobic interactions
-
COO-
l
H3N - C - H
l
CH
/ \
H3C CH3
- Valine (Val)
- Aliphatic R group
- Highly hydrophic R group
- Participates in hydrophobic interactions
-
COO-
l
H3N - C - H
l
H3C - C - H
l
CH2
l
CH3
- Isoleucine (Ile)
- Aliphatic R group
- Highly hydrophobic R group
- Participates in hydrophobic interactions
-
COO-
l
H3N - C - H
l
CH2
l
CH
/ \
H3C CH3
- Leucine (Leu)
- Aliphatic R group
- Highly hydrophobic R group
- Participates in hydrophobic interactions
-
COO-
l
H3C - C - H
l
CH2
l
// \
l ll
\\ /
- Phenylalanine (Phe)Aromatic R group
- Highly Hyrdophobic R group
- Participates in hydrophobic interactions
-
COO-
l
H3N - C - H
l
CH2
l
// \ / \\
l ll l
\\ / --NH
- Tryptophan (Trp)
- Aromatic R group - heterocyclic
- Hydrophobic, bulky
- Participates in hydrophobic interactions
- Forms hydrogen bonds
- - H-donor
-
COO-
l
H3N - C - H
l
CH2
l
CH2
l
S
l
CH3
- Methionine (Met)
- Aliphatic R group
- Hydrophobic
- Participates in hydrophobic interactions
- Sulfur containing side group (thioether)
-
COO-
l
H3N - C - H
/ \
H2C CH2
\ /
CH2
- Proline (pro)
- Aliphatic side chain with distinctive cyclic structure
- Secondary amine group
- Imino acid (not actually)
- Hydrophobic
-
COO-
l
H3N - C - H
l
H
- Glycine (Gly)
- Achiral
- Weakly Polar
- Very small -> flexible
-
COO-
l
H3N - C - H
l
CH2
l
OH
- Serine (Ser)
- Polar, uncharged
- Contains hydroxyl group
- Forms hydrogen bonds
- Typically a H-donor
- Can be modified? (due to oxygen)
-
COO-
l
H3C - C - H
l
H - C - OH
l
CH3
- Threonine (Thr)
- Polar, uncharged
- Contains hydroxyl group
- Forms hydrogen bonds
- Typically a H-donor
- Can be phosphorylated
-
COO-
l
H3N - C - H
l
CH2
l
// \
l ll
\\ /
l
OH
- Tyrosine (Tyr)
- Weakly polar, uncharged
- Aromatic R group
- Phenol
- Can participate in hydrophobic interactions
- Contains hydroxyl group
- Froms hyrdogen bonds
- Typically a H-donor
- Can be phosphorylated
-
COO-
l
H3N - C - H
l
CH2
l
SH
- Cysteine (Cys)
- Polar, uncharged
- Sulfur containing side group (thiol group - SH)
- Can form hyrdogen bonds
- Can form a thiolate anion (S-)
- Forms disuplide bonds with another Cys
-
COO-
l
H3N - C - H
l
CH2
l
C
/ \\
H2N O
- Asparagine (Asn)
- Amide containing side chain
- Carboxamide functional group
- Polar,noncharged
- Forms hydrogen bonds
- H-bond donor and acceptor
-
COO-
l
H3N - C - H
l
CH2
l
CH2
l
C
/ \\
H2N O
- Glutamine (Gln)
- Amide containing side chain
- Carboxamide functional group
- Polar, noncharged
- Forms hydrogen bonds
- H-bond donor and acceptor
-
COO-
l
H3N - C - H
l
CH2
l
// \
l llN
HN--
- Histidine (His)
- Side chain can be acidic or basic at neutral pH (imidazole ring)
- Polar, charged/uncharged
- His residues important in many enzyme catalyzed reactions
- Proton donor (acid)/acceptor (base)
- Hydrogen bonding capability - proton donor or acceptor
-
COO-
l
H3N - C - H
l
CH2
l
COO-
- Aspartate (Asp)
- Negatively charged R group at pH 7
- second carboxyl group
- acidic amino acid
- Very polar
- Forms hydrogen bonds
- H-bond acceptor
- At pH 1 called aspartic acid
-
COO-
l
H3N - C - H
l
CH2
l
CH2
l
COO-
- Glutamate (Glu)
- Negatively charged R group at pH 7
- second carboxyl group
- acidic amino acid
- Very polar
- Froms hyrdogen bonds
- H-bond acceptor
- At pH 1 called glutamic acid
-
COO-
l
H3N - C - H
l
CH2
l
CH2
l
CH2
l
CH2
l
+NH3
- Lysine (Lys)Positively charged side group at pH 7
- basic amino acid
- Side group contains an amino group
- contains 2 primary amino groups
- Forms hydrogn bonds
- H-bond donor
- Very polar
-
COO-
l
H3N - C - H
l
CH2
l
CH2
l
CH2
l
NH
l
C
/ \\+
H2N NH2
- Arginine (Arg)
- Positively charged side group at pH 7
- guanido group
- basic amino acid
- never deprotonated under physiolocial conditions
- Very polar
- Forms hydrogen bonds
- H-bond donor
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