Constitution of the Deferriform of the Albomycins δ₁, δ₂ and ε

Abstract

Fig. 1. Molecular structure of complex 2 in the crystal (50% probability thermal ellipsoids). The carbonyl groups are represented schematically and the given bond lengths are averages for the respective equivalent bonds. Space group P2,/c, u = 1402.3(6), b= 1 l21.8(4), c= 1954.2(5) pm, 8=92.83 (3)", p,,,,,=2.89,~,,,=2.87 (k0.05) g.cm-', Z = 4 ; 4392 reflections (I> ISo(l)), 215 parameters (measurement: Syntex P3, solution: She1 XTL), R , =0.084. The trinuclear complex Re3(CO),,COOH with the structural element 1 H ,O-Re 0-Re Re-C\has recently been isolated[41. As in this compound, the ReCO, moiety in 2 is planar. The entire six-membered ring is also almost planar. The CO distances of the CO, group correspond to those in the carboxylate anion, and the Re-C bond is almost a o single bond; hence, 2 can best be considered as a metal carboxylate. A carbene structure ,0-Re 0-Re Re=C has little weighting. In the Re(CO), and Re(CO), moieties a shortening of the Re-C bond and a lengthening of the CO bond via the trans-sited donor atoms of the C 0 2 group can clearly be recognized.2 is of interest since it represents a novel type of coordination of carbon dioxide in C 0 2 complexes[5'. For the CS2 ligand, for which numerous types of coordination are known@], covalent bridging of three metal atoms has, to the best of our knowledge, not been observed to date.The bond between a carbonylrhenium group and oxygen donors is apparently very stable, and we were able to obtain the very stable complexes (OC),ReOCHO, (OC),Re(02CC02)Re(CO),, (OCh Re(C,OdWCO),, (OC),ReONO, (OC),ReN02 (mixture of isomers) and (OC),ReON02 by allowing (OC)$eFBF, to react with formate, oxalate, squarate, nitrite, and nitrate, respectively.(1981) 81. Previously, an analogous complex (OC)5ReFAsF5 has been re-

MccE Provides Resistance to Protein Synthesis Inhibitor Microcin C by Acetylating the Processed Form of the Antibiotic

“…Because either aspartyl, glutamyl, or leucyl moieties are acetylated, the acetyl group must be located on the ␣-amino group. (21). Upon entering cells through the FhuA ferrichrome transporter, albomycin is processed by aminopeptidases with the release of a nonhydrolyzable seryl-thioxylofuranosyl pyrimidine (22) that inhibits seryltRNA synthetase (23).…”

Total synthesis and antimicrobial evaluation of natural albomycins against clinical pathogens

“…The structures of albomycins were fully elucidated by Benz and coworkers in 1982 13,14 , 35 years after their initial isolation. Albomycins δ 1 ( 1a ), δ 2 ( 1b ), and ε ( 1c ) are all composed of a tri-δ- N -hydroxy-L-ornithine peptide siderophore and a thionucleoside warhead with six consecutive chiral centers, and differ only in the C4 substituent (R) of the pyrimidine nucleobase (Fig.…”

A Biosynthetic Pathway for BE-7585A, a 2-Thiosugar-Containing Angucycline-Type Natural Product

“…These include BE-7585A ( 1 ),2 rhodonocardins ( 5 ),4 lincomycins ( 6 ),5 celesticetin,6 calicheamicins ( 7 ),7 esperamicins,8 namenamicin,9 shishijimicins,10 albomycins ( 8 )11 and SB-21745212 from microorganisms; kotalanol,13 salacinol14 and glucosinolates15 from plants; and 5-thio-D-mannose16 from the marine sponge Clathria pyramida (although the actual producer might be its symbiont). The biosynthetic gene clusters for some of the compounds produced by bacteria have been identified,17–19 but the pathway and mechanisms of the thiosugar biosynthesis in each case remain obscure.…”