[Mo12S12O12(OH)12(H2O)6]: ein cyclischer molekularer Cluster aus [Mo2S2O2]2+-Baueinheiten

[W16S16O16(OH)16(H2O)4(C5H6O4)2]4−: A Flexible, Pillared Oxothiotungstate Wheel

“…[5] The rapamycin polyketide synthase (PKS) is a modular system in which 14 chain extension modules are housed in three giant multimodular proteins (RAPS 1 ± 3). [4,5] The polyketide origin of rapamycin has been verified through feeding studies with labeled precursors.…”

“…[5] The rapamycin polyketide synthase (PKS) is a modular system in which 14 chain extension modules are housed in three giant multimodular proteins (RAPS 1 ± 3). [4,5] The polyketide origin of rapamycin has been verified through feeding studies with labeled precursors. [6] Rapamycin, FK 506, and FK 520 share in common an unusual substituted cyclohexane ring, the origins of which have been traced to shikimic acid for rapamycin [7] and FK 520, [8] and which undergoes O-methylation post-PKS during the biosynthesis of FK 506.…”

“…Rapamycin the starter unit of the rapamycin PKS brings into question the function of an apparently catalytically competent enoyl reductase domain (ER) present in the initiation module, [5] the structure of which is also conserved for the PKSs of FK 506 [11] and FK 520. [12] The steps between shikimic acid (2) and 1 for FK 520 have been elucidated and are described in Scheme 1.…”

“…[4] Two years ago, we reported the synthesis and characterization of the neutral ring-shaped polyoxothio molybdenum compound [Mo 12 S 12 O 12 (OH) 12 -(H 2 O) 6 ]. [5] The cyclic architecture of this cluster delimits a central cavity which has a significant cationic character and is the origin of striking properties related to supramolecular [6] or host ± guest chemistry. [7] Anionic reagents such as phosphate or dicarboxylate ions have been inserted into the cavity replacing the water molecules which initially line the cavity.…”

“…Such a result illustrates the high flexibility of a cyclic arrangement, also observed in the analogous Mo 12cyclic oxothiomolybdate compound [7] in which the {Mo 12 } ring can adopt circular or pronounced elliptic geometry provoking strong variations in the Mo-Mo-Mo angles which change from 1508 to 1308 and 1808. [5] The two conformations of {W 16 } can be viewed as two snapshots of the molecule, each reflecting the dynamic of the wheel in aqueous solution and the sensitivity of the system to weak interactions. the methylene unit of the glutarate alkyl chain (d 0.22 and À 0.26).…”