1187452-09-0Relevant articles and documents
Donor Promiscuity of a Thermostable Transketolase by Directed Evolution: Efficient Complementation of 1-Deoxy-d-xylulose-5-phosphate Synthase Activity
Saravanan, Thangavelu,Junker, Sebastian,Kickstein, Michael,Hein, Sascha,Link, Marie-Kristin,Ranglack, Jan,Witt, Samantha,Lorillière, Marion,Hecquet, Laurence,Fessner, Wolf-Dieter
, p. 5358 - 5362 (2017)
Enzymes catalyzing asymmetric carboligation reactions typically show very high substrate specificity for their nucleophilic donor substrate components. Structure-guided engineering of the thermostable transketolase from Geobacillus stearothermophilus by directed in vitro evolution yielded new enzyme variants that are able to utilize pyruvate and higher aliphatic homologues as nucleophilic components for acyl transfer instead of the natural polyhydroxylated ketose phosphates or hydroxypyruvate. The single mutant H102T proved the best hit toward 3-methyl-2-oxobutyrate as donor, while the double variant H102L/H474S showed highest catalytic efficiency toward pyruvate as donor. The latter variant was able to complement the auxotrophic deficiency of Escherichia coli cells arising from a deletion of the dxs gene, which encodes for activity of the first committed step into the terpenoid biosynthesis, offering the chance to employ a growth selection test for further enzyme optimization.
Broadening deoxysugar glycodiversity: Natural and engineered transaldolases unlock a complementary substrate space
Rale, Madhura,Schneider, Sarah,Sprenger, Georg A.,Samland, Anne K.,Fessner, Wolf-Dieter
supporting information; experimental part, p. 2623 - 2632 (2011/04/16)
The majority of prokaryotic drugs are produced in glycosylated form, with the deoxygenation level in the sugar moiety having a profound influence on the drug's bioprofile. Chemical deoxygenation is challenging due to the need for tedious protective group manipulations. For a direct biocatalytic de novo generation of deoxysugars by carboligation, with regiocontrol over deoxygenation sites determined by the choice of enzyme and aldol components, we have investigated the substrate scope of the F178Y mutant of transaldolase B, TalBF178Y, and fructose 6-phosphate aldolase, FSA, from E. coli against a panel of variously deoxygenated aldehydes and ketones as aldol acceptors and donors, respectively. Independent of substrate structure, both enzymes catalyze a stereospecific carboligation resulting in the D-threo configuration. In combination, these enzymes have allowed the preparation of a total of 22 out of 24 deoxygenated ketose-type products, many of which are inaccessible by available enzymes, from a [3 -8] substrate matrix. Although aliphatic and hydroxylated aliphatic aldehydes were good substrates, D-lactaldehyde was found to be an inhibitor possibly as a consequence of inactive substrate binding to the catalytic Lys residue. A 1-hydroxy-2-alkanone moiety was identified as a common requirement for the donor substrate, whereas propanone and butanone were inactive. For reactions involving dihydroxypropanone, TalBF178Y proved to be the superior catalyst, whereas for reactions involving 1-hydroxybutanone, FSA is the only choice; for conversions using hydroxypropanone, both TalBF178Y and FSA are suitable. Structure-guided mutagenesis of Ser176 to Ala in the distant binding pocket of TalBF178Y, in analogy with the FSA active site, further improved the acceptance of hydroxypropanone. Together, these catalysts are valuable new entries to an expanding toolbox of biocatalytic carboligation and complement each other well in their addressable constitutional space for the stereospecific preparation of deoxysugars.
Hydrodeamination of β-enamino ketones to 1,2-dideoxy-d-threo-3-hexulose via palladium
Lin, Zi-Ping,Lin, Hui-Chang,Wu, Hsu-Hsuan,Chou, Hsiu-Wen,Lin, Shao-Kai,Sung, Kuan-Chin,Wong, Fung Fuh
supporting information; scheme or table, p. 5120 - 5122 (2009/11/30)
β-Enamino ketones were successfully synthesized in good to excellent yields by reaction of hex-1-en-3-uloses with amines. After hydrogenation on palladium catalyst, β-enamino ketones effectively underwent hydrodeamination and were converted to the corresp
