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The 20 amino acids.

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Presentation on theme: "The 20 amino acids."— Presentation transcript:

1 The 20 amino acids

2 A Ala Alanine Small Hydrophobic Helix: ++ Strand: – Turn: – –
Mutate to Ala if you have to mutate but have no clue to which residue

3 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)

4 D Asp Aspartate Intermediately large Hydrophilic Negatively charged
Helix: - (but ++ at N-terminus) Strands: – – Turn: ++ Often in active sites Can bind ions (mainly calcium)

5 E Glu Glutamate Large Hydrophilic Negatively charged Helix: ++
Strand: 0 Turn: –

6 F Phe Phenylalanine Large Hydrophobic Aromatic Helix: + Strand: ++
Turn: – –

7 G Gly Glycine Smallest residue No side chain Helix: – – Strand: –-
Hydrophobicity undetermined Very flexible Star of the turns Helix: – – Strand: –- Turn: ++

8 H His Histidine Large Hydrophilic Charge (depends on the environment):
Positive Neutral Negative No secondary structure preference Often in active sites Can bind metal ions (mainly Zn, Ni, Cu)

9 I Ile Isoleucine Intermediately large Hydrophobic Helix: + Strand: ++
Turn: – –

10 K Lys Lysine Large Hydrophilic Positively charged Helix: ++ Strand: 0
Turn: 0 Long, flexible side chain

11 L Leu Leucine Intermediately large Hydrophobic Helix: ++ Strand: +
Turn: – –

12 M Met Methionine Large Hydrophobic Sulfur containing Helix: ++
Strand: + Turn: – – Non-reactive sulfur which can bind metal ions Often the first residue of the sequence and therefore at the surface (forced marriage)

13 N Asn Asparagine Intermediately large Hydrophilic Helix: – – Strand: -
Turn: ++ Can bind ions (Ca) but not as well as its isosteric partner Asp

14 P Pro Proline Small Hydrophobic
Helix: – – (except at the first position) Strand: – – Turn: ++ Imino acid No backbone proton Pre-bend for turns (forced marriage)

15 Q Gln Glutamine Large Hydrophilic Helix: + Strand: 0 Turn: 0
Isosteric with Glu

16 R Arg Arginine Large Hydrophilic Positively charged
No secondary structure preference Contains a rigid guanidinium group

17 S Ser Serine Small Intermediate hydrophobicity Alcoholic Helix: –
Strand: – Turn: ++ Often in active sites (with Asp and His) Can bind calcium

18 T Thr Threonine Small Intermediate hydrophobicity Alcoholic Helix: 0
Strand: ++ Turn: 0 Can bind calcium

19 V Val Valine Small Hydrophobic Helix: 0 Strand: ++ Turn: – –
Isosteric with Thr

20 W Trp Tryptophan Largest residue Hydrophobic Aromatic Helix: 0
Strand: ++ Turn: 0 Most conserved residue

21 Y Tyr Tyrosine Large Intermediate hydrophobicity Aromatic Alcoholic
Helix: – Strand: ++ Turn: 0


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