Crystal and molecular structure of the quinoxaline antibiotic analog TANDEM (des-N-tetramethyltriostin A)

The crystal structure of TANDEM (des-N-tetramethyltriostin A), a synthetic analogue of the quinoxaline antibiotic triostin A, has been determined independently at -135 and 7 'C and refined to R values of 0.088 and 0.147, respectively. The molecule has approximate 2-fold symmetry, with the quinoxaline chromophores and the disulfide cross-bridge projecting from opposite sides of the peptide ring. The quinoxaline groups are nearly parallel to each other and separated by about 6.5 A. The peptide backbone resembles a distorted antiparallel 13 ribbon joined by intramolecular hydrogen bonds N-H(LVal)--O(L-Ala). At low temperatures, the TANDEM molecule is surrounded by a regular first- and second-order hydration sphere containing 14 independent water molecules. At room temperature, only the first-order hydration shell is maintained. Calculations of the interplanar separation of the quinoxaline groups as a function of their orientation with respect to the peptide ring support the viability of TANDEM to intercalate bifunctionally into DNA.

Dinner celebrating Aenny Catzenstein's 80th birthday.

seen on the photograph from left to right: Susan, Maren and Olga Matthiesen

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday; London.

Front row l-r: Beatrice Durand, Francine Durand and Aenny Catzenstein, the boys are Ara-Serge Donabedian and Patrick Matthiesen and the adults are Susan Prior, Francis Matthiesen, Maren Matthiesen, Nino Fabri and Olga Matthiesen,

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday party; London.

Dinner scene with Franz Mattheisen left, daughter Susan Mattheisen next to him, next daughter Maren Matthiesen, his wife Olga Matthiesen at the end of the table. Beatrice Durand is facing the camera

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday; London.

Front row l-r: Francine Durand, Beatrice Durand and Aenny Catzenstein, the boys are Ara-Serge Donabedian and Patrick Matthiesen and the adults are Susan Prior, Francis Matthiesen, Maren Matthiesen, Nino Fabri and Olga Matthiesen,

Studio portrait of the wood merchant Hermann Judey with his stepson Paul Portraits Family

Paul was the son from a previous marriage of Hermann's first wife Olga Judey nee Fischmann

Studio portrait of Paul and Rahel Portraits Couples

Paul was the son from a previous marriage of Hermann Judey's first wife Olga Judey nee Fischmann

Paul and Rahel in a car with an unidentified chauffeur; Berlin Portraits Couples

Paul was the son from a previous marriage of Hermann Judey's first wife Olga Judey nee Fischmann

Judey family playing cricket Portraits Family

l-r: Hermann (father), Mary (Miriam), Olga (mother), Lydia, Sina and Jacob

Dinner celebrating Aenny Catzenstein's 80th birthday.

seen on the photograph from left to right: Susan, Maren and Olga Matthiesen

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday; London.

Front row l-r: Beatrice Durand, Francine Durand and Aenny Catzenstein, the boys are Ara-Serge Donabedian and Patrick Matthiesen and the adults are Susan Prior, Francis Matthiesen, Maren Matthiesen, Nino Fabri and Olga Matthiesen,

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday party; London.

Dinner scene with Franz Mattheisen left, daughter Susan Mattheisen next to him, next daughter Maren Matthiesen, his wife Olga Matthiesen at the end of the table. Beatrice Durand is facing the camera

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday; London.

Front row l-r: Francine Durand, Beatrice Durand and Aenny Catzenstein, the boys are Ara-Serge Donabedian and Patrick Matthiesen and the adults are Susan Prior, Francis Matthiesen, Maren Matthiesen, Nino Fabri and Olga Matthiesen,