Amino acid clusters

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Amino acid clusters

• Bo Liu

Department of Physics and Astronomy
University of Aarhus Denmark
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University of Aarhus
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Introductions to biomolecules
Proteins
DNAs
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Building Mansions
Nucleotides
Amino Acids (20 types)
Adenosine 5-monophosphate (AMP)
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Amino Acid
Protein
peptide

• Amino acid

Phenylalanine
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Mononucleotide
DNA RNA
Oligonucleotide

• Mononucleotide

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Peptide and Oligonucleotide

• Peptide

Peptide bond

• Oligonucleotide

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Experimental layout
collision cell
R 2 m B 1.4 T
Magnet
Electrostatic analyzer
0 V
Channeltron detector
?50 kV
ESI source
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Appearance sizes of multiply charged clusters
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Appearance Sizes (na)
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Magic number
Discovery of C60 (1985)
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Laser vaporization and cooling in a supersonic
beam
(Magic numbers)
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fullerene
H.W. Kroto, J.R.Heath, S.C. OBrien, R.F. Curl
and R.E. Smalley Nature 318, (1985) 162
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(Magic numbers)
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Takatas et al. Anal. Chem 75,1514 (2003)
(Magic numbers)
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Does chirality influence the magic numbers?
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Serine Octamer
YES !
Julian et al JPC B 106 1219 (2002)
Preference for homochirality
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Important discovery

• Only L-amino acids exist?

1 For some reason, L-amino acids dominates over
D-amino acids
2 Chirality preference
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Mixture of L and D
D only
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Statistic process
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Conclusions

• Appearence sizes scale with charge squared as
  predicted by Lord Rayleigh
• Magic numbers also apply to clusters made from
  large molecules
• Chiral recognition plays an important role for
  amino acid clusters
• Electron capture induced fragmentations also
  apply to multiply charged clusters