René Traber

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The biosynthesis of (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine (abbreviation: Bmt, systematic name: 2(S)-amino-3(R)-hydroxy-4(R)-methyl-6(E)-octenoic acid) is proposed to involve two principal phases: the formation of a polyketide backbone and a subsequent transformation process to the final product. Here we report on the identification of(More)
Cyclic undecapeptide cyclo-[MeBmt(1)-Abu(2)-MeGly(3)-MeLeu(4)-Val(5)-MeLeu(6)-Ala(7)-D-Ala(8)-MeLeu(9)-MeLeu(10)-MeVal(11)], the immunosuppressive and antifungal antibiotic cyclosporin A (CsA), was reported to interfere with the MDR1 P-glycoprotein (Pgp), a transmembranous adenosine 5'-triphosphate binding cassette (ABC) transporter with phospholipid(More)
Cyclosporin A (ciclosporin), a potent and clinically important immunosuppressive drug (Sandimmun), represents the main component of a group of over 25 closely related, cyclic undecapeptides produced by the fungus Tolypocladium inflatum. By feeding experiments using DL-alpha-allylglycine as precursor, specific incorporation in position 2 was attained leading(More)
The human formylpeptide receptor (FPR) is a seven-transmembranous G-protein-coupled receptor (7TM-GPCR) for chemotactic peptides of bacterial origins, possibly involved in the recruitment and activation of neutrophils in various inflammatory diseases of mucosal epithelia. Mutational analyses suggest that interactions of formylated peptides with FPR occur on(More)
Cyclosporin A (Sandimmune) increased the in vitro susceptibility of 'parental' and 'multidrug-resistant' (MDR) chinese hamster ovary (CHO) cell lines to three anti-tumour drugs: colchicine, daunomycin, and vincristine. Several immunosuppressive or non-immunosuppressive derivatives of cyclosporin (Cs) were compared for their ability to sensitise both(More)
The recently discovered multifunctional polypeptide cyclosporin synthetase is capable of synthesizing the cyclic undecapeptide cyclosporin A in a batch reaction. Substrates are the unmethylated constitutive amino acids of cyclosporin A. Exchange of one or more of these by various amino acids gives a picture of the substrate specificity of the enzyme in(More)