Download The 20 amino acids

The 20 amino acids
A
Ala
Alanine
 Small
 Hydrophobic
 Helix: ++
 Strand: –
 Turn: – –
 Mutate to Ala if you have to mutate but have no clue
to which residue
C
Cys
Cysteine
 Small
 Hydrophobic
 Sulfur containing
 Helix: –
 Strand: +
 Turn: +
 The SH-group is very reactive:
 Can make Cys-Cys bridges
 Can bind metal ions (especially Zn and Cu)
D
Asp
Aspartate
 Intermediately large
 Hydrophilic
 Negatively charged
 Helix: 0 (++ at N-terminus)
 Strands: – –
 Turn: ++
 Often in active sites
 Can bind ions (mainly calcium)
E
Glu
Glutamate
 Large
 Hydrophilic
 Negatively charged
 Helix: ++
 Strand: 0
 Turn: –
F
Phe
 Large
 Hydrophobic
 Aromatic
 Helix: 0
 Strand: ++
 Turn: – –
Phenylalanine
G
Gly
Glycine
 Smallest residue
 No side chain
 Hydrophobicity undetermined
 Very flexible
 Star of the turn
 Helix: – –
 Strand: –
 Turn: ++
H
His
Histidine
 Large
 Hydrophilic
 Charge (depending on the environment):
 Positive
 Neutral or
 Negative
 No secondary structure preference
 Often in active sites
 Can bind metal ions (mainly Zn, Ni, Cu)
I
Ile
Isoleucine
 Intermediately large
 Hydrophobic
 Helix: 0
 Strand: ++
 Turn: – –
K
Lys
Lysine
 Large
 Hydrophilic
 Positively charged
 Helix: ++
 Strand: –
 Turn: 0
 Long, flexible side chain
L
Leu
Leucine
 Intermediately large
 Hydrophobic
 Helix: ++
 Strand: +
 Turn: – –
M Met
Methionine
 Large
 Hydrophobic
 Sulfur containing
 Helix: ++
 Strand: 0
 Turn: – –
 Non-reactive sulfur which can bind metal ions
 Often the first residue of the sequence
N
Asn
Asparagine
 Intermediately large
 Hydrophilic
 Helix: – –
 Strand: 0
 Turn: ++
 Can bind ions (Ca) but not as well as its isosteric
partner Asp
P
Pro
Proline
 Small
 Hydrophobic
 Helix: – – (except at the first position)
 Strand: – –
 Turn: ++
 Imino acid
 No backbone proton
 Pre-bend for turns
Q
Gln
 Large
 Hydrophilic
 Helix: +
 Strand: 0
 Turn: 0
 Isosteric with Glu
Glutamine
R
Arg
Arginine
 Large
 Hydrophilic
 Positively charged
 No secondary structure preference
 Contains a rigid guanidinium group
S
Ser
Serine
 Small
 Intermediate hydrophobicity
 Alcoholic
 Helix: –
 Strand: –
 Turn: ++
 Often in active sites (with Asp and His)
 Can bind calcium
T
Thr
Threonine
 Small
 Intermediate hydrophobicity
 Alcoholic
 Helix: 0
 Strand: +
 Turn: 0
 Can bind calcium
V
Val
 Small
 Hydrophobic
 Helix: 0
 Strand: ++
 Turn: – –
 Isosteric with Thr
Valine
W Trp
Tryptophan
 Largest residue
 Hydrophobic
 Aromatic
 Helix: 0
 Strand: ++
 Turn: 0
 Most conserved residue
Y
Tyr
Tyrosine
 Large
 Intermediate hydrophobicity
 Aromatic
 Alcoholic
 Helix: –
 Strand: ++
 Turn: 0