524-14-1Relevant articles and documents
Identification of a nonaketide product for the iterative polyketide synthase in biosynthesis of the nine-membered enediyne C-1027
Chen, Xiaolei,Guo, Zu-Feng,Lai, Pok Man,Sze, Kong Hung,Guo, Zhihong
, p. 7926 - 7928 (2010)
Not octa- but nonaketide: The nine-membered enediyne core polyketide synthase SgcE efficiently synthesizes a nonaketide in the absence of any assisting proteins (see scheme), contrary to the suggestion that an octaketide is the product of the synthase under assistance from a thioesterase. This finding redefines the catalytic functions of the polyketide synthase. CoA=coenzyme A.
Cloning, expression, and enzymatic activity of Acinetobacter baumannii and Klebsiella pneumoniae acetyl-coenzyme A carboxylases
Alves, Juliano,Westling, Lucas,Peters, Eric C.,Harris, Jennifer L.,Trauger, John W.
, p. 103 - 111,9 (2011)
Pathogenic Gram-negative bacteria are a major public health concern because they are causative agents of life-threatening hospital-acquired infections. Due to the increasing rates of resistance to available antibiotics, there is an urgent need to develop new drugs. Acetyl-coenzyme A carboxylase (ACCase) is a promising target for the development of novel antibiotics. We describe here the expression, purification, and enzymatic activity of recombinant ACCases from two clinically relevant Gram-negative pathogens, Acinetobacter baumannii and Klebsiella pneumoniae. Recombinant ACCase subunits (AccAD, AccB, and AccC) were expressed and purified, and the holoenzymes were reconstituted. ACCase enzyme activity was monitored by direct detection of malonyl-coenzyme A (malonyl-CoA) formation by liquid chromatography tandem mass spectrometry (LC-MS/MS). Steady-state kinetics experiments showed similar kcat and K M values for both enzymes. In addition, similar IC50 values were observed for inhibition of both enzymes by a previously reported ACCase inhibitor. To provide a higher throughput assay suitable for inhibitor screening, we developed and validated a luminescence-based ACCase assay that monitors ATP depletion. Finally, we established an enzyme activity assay for the isolated AccAD (carboxyltransferase) subunit, which is useful for determining whether novel ACCase inhibitors inhibit the biotin carboxylase or carboxyltransferase site of ACCase. The methods described here could be applied toward the identification and characterization of novel inhibitors.
Enzymatic total synthesis of rabelomycin, an angucycline group antibiotic
Kharel, Madan Kumar,Pahari, Pallab,Lian, Hui,Rohr, Juergen
, p. 2814 - 2817 (2010)
(Figure presented) A one-pot enzymatic total synthesis of angucycline antibiotic rabelomycin was accomplished, starting from acetyl-CoA and malonyl-CoA, using a mixture of polyketide synthase (PKS) enzymes of the gilvocarcin, ravidomycin, and jadomycin biosynthetic pathways. The in vitro results were compared to in vivo catalysis using analogous sets of enzymes.
Rapid preparation of (methyl)malonyl coenzyme A and enzymatic formation of unusual polyketides by type III polyketide synthase from Aquilaria sinensis
Gao, Bo-Wen,Wang, Xiao-Hui,Liu, Xiao,Shi, She-Po,Tu, Peng-Fei
supporting information, p. 1279 - 1283 (2015/03/14)
(Methyl)malonyl coenzyme A was rapidly and effectively synthesized by a two-step procedure involving preparation of N-hydroxysuccinimidyl (methyl)malonate from (methyl)Meldrum's acid, and followed by transesterification with coenzyme A. The synthesized (methyl)malonyl coenzyme A could be well accepted and assembled to 4-hydroxy phenylpropionyl coenzyme A by type III polyketide synthase from Aquilaria sinensis to produce dihydrochalcone and 4-hydroxy-3,5-dimethyl-6-(4-hydroxyphenethyl)-2H-pyrone as well as 4-hydroxy-3,5-dimethyl-6-(5-(4-hydroxyphenyl)-3-oxopentan-2-yl)-2H-pyrone.
Crystal structures of Acetobacter aceti succinyl-coenzyme A (CoA):Acetate CoA-transferase reveal specificity determinants and illustrate the mechanism used by class i CoA-transferases
Mullins, Elwood A.,Kappock, T. Joseph
, p. 8422 - 8434 (2013/01/15)
Coenzyme A (CoA)-transferases catalyze transthioesterification reactions involving acyl-CoA substrates, using an active-site carboxylate to form covalent acyl anhydride and CoA thioester adducts. Mechanistic studies of class I CoA-transferases suggested that acyl-CoA binding energy is used to accelerate rate-limiting acyl transfers by compressing the substrate thioester tightly against the catalytic glutamate [White, H., and Jencks, W. P. (1976) J. Biol. Chem. 251, 1688-1699]. The class I CoA-transferase succinyl-CoA:acetate CoA-transferase is an acetic acid resistance factor (AarC) with a role in a variant citric acid cycle in Acetobacter aceti. In an effort to identify residues involved in substrate recognition, X-ray crystal structures of a C-terminally His6-tagged form (AarCH6) were determined for several wild-type and mutant complexes, including freeze-trapped acetylglutamyl anhydride and glutamyl-CoA thioester adducts. The latter shows the acetate product bound to an auxiliary site that is required for efficient carboxylate substrate recognition. A mutant in which the catalytic glutamate was changed to an alanine crystallized in a closed complex containing dethiaacetyl-CoA, which adopts an unusual curled conformation. A model of the acetyl-CoA Michaelis complex demonstrates the compression anticipated four decades ago by Jencks and reveals that the nucleophilic glutamate is held at a near-ideal angle for attack as the thioester oxygen is forced into an oxyanion hole composed of Gly388 NH and CoA N2″. CoA is nearly immobile along its entire length during all stages of the enzyme reaction. Spatial and sequence conservation of key residues indicates that this mechanism is general among class I CoA-transferases.
Synthesis of (R)-mellein by a partially reducing iterative polyketide synthase
Sun, Huihua,Ho, Chun Loong,Ding, Feiqing,Soehano, Ishin,Liu, Xue-Wei,Liang, Zhao-Xun
supporting information; experimental part, p. 11924 - 11927 (2012/09/08)
Mellein and the related 3,4-dihydroisocoumarins are a family of natural products with interesting biological properties. The mechanisms of dihydroisocoumarin biosynthesis remain largely speculative today. Here we report the synthesis of mellein by a partially reducing iterative polyketide synthase (PR-PKS) as a pentaketide product. Remarkably, despite the head-to-tail homology shared with several fungal and bacterial PR-PKSs, the mellein synthase exhibits a distinct keto reduction pattern in the synthesis of the pentaketide. We present evidence to show that the ketoreductase (KR) domain alone is able to recognize and differentiate the polyketide intermediates, which provides a mechanistic explanation for the programmed keto reduction in these PR-PKSs.
