SYNTHESIS%20OF%20PEPTIDE%20NUCLEIC%20ACID%20(PNA)%20OLIGOMERS

1
SYNTHESIS OF PEPTIDE NUCLEIC ACID (PNA)
OLIGOMERS AND THEIR CONJUGATES
Györgyi Kovács 1 , Zoltán Timár 1 , Zoltán
Kupihár 1 , Zoltán Kele 1, Péter Forgó 2, Lajos
Kovács 1
University of Szeged, 1 Institute of Medicinal
Chemistry, Laboratory Of Nucleic Acid, 2
Department Of Organic Chemistry, 6720 Szeged,
Dóm tér 8
Introduction
Antisense and antigene effect ? molecular biology
and medicinal chemistry
Advantage in vivo stability and strong
hybridization disadvantage poor cellular
uptake and low activity Possible
solutions PNA-peptide and PNA-oligonucleotide
conjugates
Schematic representation of PNA oligomers
X R
T -
C 4tBuBz
A An
G Ibu
Synthesis of our own PNA monomers using Fmoc/acyl
protecting groups, as they are compatible both
with peptide and oligonucleotide synthesis
protocols (conjugate).
Aims
Synthesis of PNA oligomers, PNA-peptide and
PNA-oligonucleotide conjugates from our monomers
Results
Problems with the oligomer synthesis and the
proposed solutions
optimization of the coupling step (efficiency of
coupling agents in solution phase)
I.
(HBTU/HOBt/DIPEA/Lutidine) lt (HATU/ DIPEA/
Lutidine) lt BET/ DIPEA lt CMP/ DIPEA 76
90 98-99 gt 99
Selection of the solid phase
II.
compatible with peptide and oligonucleotide
synthesis, acyl and PNA removal in one step with
aq. NH3 but oligo ethylene-glycol chains
disturb the analysis
TentaGel
II.1.
The mass spectra of PNAs, prepared on Tentagel,
showed M70 ions (not complete removal of Ibu)
and values smaller than M
II.2.
to check the efficiency of the coupling and acyl
protecting group removal (the most critical steps)
Wang
CPG
II.3.
Synthesis of the PNA-oligonucleotide conjugates
III. removal of the acyl protecting group
aq. NH3
order of stability Ibu gt An gt 4-tBuBz
H-Gly-(gIbu)5-Lys-OH
50 C, ON
PNA synthesis
monomer HATU DIPEA lutidine 3 2.7 3.3
3.3 20 minutes DMF
PNA-oligonucleotide conjugate
Peptide-PNA conjugate
PNA-linker2-5'-oligonucleotide- 3'
H-Cys-ArgArgMetLysTrpLysLys-OH H-Cys(Npys)-gIbua
AnaAnc4tBuBzaAntc4tBuBzaAntgIbugIbutc4tBuBzgIbut
-Lys-OH
5'-oligonucleotide-3'-linker-PNA
Financial support OTKA T 022551 FKFP 0597/1999
linker
Dr. Gyula Sági et al.