Philippe Schmitt

Cloning, expression, and characterization of DNA polymerase I from the hyperthermophilic archaea Thermococcus fumicolans.

Abstract The DNA polymerase I gene of a newly described deep-sea hydrothermal vent Archaea species, Thermococcus fumicolans, from IFREMERSs collection of hyperthermophiles has been cloned in Escherichia coli. As in Thermococcus litoralis, the gene is split by two intervening sequences (IVS) encoding inteins inserted in sites A and C of family B DNA polymerases. The entire DNA polymerase gene, containing both inteins, was expressed at 30°C in E. coli strain BL21(DE3)pLysS using the pARHS2 expression vector. The native polypeptide precursor of 170 kDa was obtained, and intein splicing as well as ligation of the three exteins was observed in vitro after heat exposure. The recombinant enzyme was purified and some of its activities were characterized: polymerization, thermostability, exonuclease activities, and fidelity.

13H-benzo[6-7]indolo[3,2-c]quinolines(B[6,7]IQ): optimization of their DNA triplex-specific stabilizationproperties

The triple helix stabilization property of 13H-benzo[6-7]indolo[3,2-c]quinoline was significantly improved by changing the electron-donor acceptor properties of the substituent at position 10 or 11.

Synthesis and biological evaluation of (-)-6-O-desmethylcryptopleurine and analogs.

(-)-Cryptopleurine 1 is one of the most potent anti-proliferative member of the phenanthroquinolizidine class of alkaloids. We report here the synthesis of (-)-6-O-desmethylcryptopleurine (-)-2 and (-)-6-O-desmethyl-(15R)-hydroxycryptopleurine (-)-4 in their enantiomerically enriched form through a convergent synthetic route, where the chirality is introduced by the use of commercially available (R)-methyl piperidine-2-carboxylate hydrochloride 17. Anti-proliferative activities of these compounds were evaluated on a panel of four cancer cell lines, revealing that compounds (-)-2 and (-)-4 are potent cytotoxic compared to cryptopleurine.