72289-61-3Relevant academic research and scientific papers
Stereodivergent Protein Engineering of a Lipase to Access All Possible Stereoisomers of Chiral Esters with Two Stereocenters
Xu, Jian,Cen, Yixin,Singh, Warispreet,Fan, Jiajie,Wu, Lian,Lin, Xianfu,Zhou, Jiahai,Huang, Meilan,Reetz, Manfred T.,Wu, Qi
supporting information, p. 7934 - 7945 (2019/05/22)
Enzymatic stereodivergent synthesis to access all possible product stereoisomers bearing multiple stereocenters is relatively undeveloped, although enzymes are being increasingly used in both academic and industrial areas. When two stereocenters and thus four stereoisomeric products are involved, obtaining stereodivergent enzyme mutants for individually accessing all four stereoisomers would be ideal. Although significant success has been achieved in directed evolution of enzymes in general, stereodivergent engineering of one enzyme into four highly stereocomplementary variants for obtaining the full complement of stereoisomers bearing multiple stereocenters remains a challenge. Using Candida antarctica lipase B (CALB) as a model, we report the protein engineering of this enzyme into four highly stereocomplementary variants needed for obtaining all four stereoisomers in transesterification reactions between racemic acids and racemic alcohols in organic solvents. By generating and screening less than 25 variants of each isomer, we achieved >90% selectivity for all of the four possible stereoisomers in the model reaction. This difficult feat was accomplished by developing a strategy dubbed "focused rational iterative site-specific mutagenesis" (FRISM) at sites lining the enzyme's binding pocket. The accumulation of single mutations by iterative site-specific mutagenesis using a restricted set of rationally chosen amino acids allows the formation of ultrasmall mutant libraries requiring minimal screening for stereoselectivity. The crystal structure of all stereodivergent CALB variants, flanked by MD simulations, uncovered the source of selectivity.
Olefins from biomass feedstocks: Catalytic ester decarbonylation and tandem Heck-type coupling
John, Alex,Hogan, Levi T.,Hillmyer, Marc A.,Tolman, William B.
supporting information, p. 2731 - 2733 (2015/03/05)
With the goal of avoiding the need for anhydride additives, the catalytic decarbonylation of p-nitrophenylesters of aliphatic carboxylic acids to their corresponding olefins, including commodity monomers like styrene and acrylates, has been developed. The reaction is catalyzed by palladium complexes in the absence of added ligands and is promoted by alkali/alkaline-earth metal halides. Combination of catalytic decarbonylation and Heck-type coupling with aryl esters in a single pot process demonstrates the viability of employing a carboxylic acid as a "masked olefin" in synthetic processes. This journal is
Fingerprint lipolytic enzymes with chromogenic p-nitrophenyl esters of structurally diverse carboxylic acids
Qian, Le,Liu, Jia-Yan,Liu, Jia-Ying,Yu, Hui-Lei,Li, Chun-Xiu,Xu, Jian-He
, p. 22 - 26 (2012/02/06)
A series of structurally diverse chromogenic esters, including a new compound (4-nitrophenyl 2-methylpentanoate), has been synthesized, constituting an array of 17 substrates which could be applied to rapidly fingerprint the activity of lipases or esterases to reveal their substrates specificity and functional characteristics. Combined with genetic technology such as "data mining" and directed evolution, such fingerprints might be a promising platform for discovery of potentially useful enzymes in industrial application. The fingerprint of commercially available Lipase-B from Candida antarctica as a model enzyme was first measured to confirm the reliability of this method. Then three new enzymes mined from genomic libraries were successfully fingerprinted, revealing the functional characteristics of those enzymes. Among them, the enzyme SrfAD was founded with specific substrate preference towards cycloalkyl carboxylic esters and aromatic esters, making it more promising in synthetic utilities than other tested enzymes.
Directed evolution of an enantioselective lipase with broad substrate scope for hydrolysis of α-substituted esters
Engstroem, Karin,Nyhlen, Jonas,Sandstroem, Anders G.,Baeckvall, Jan-E.
supporting information; experimental part, p. 7038 - 7042 (2010/07/05)
A variant of Candida antarctica lipase A (CalA) was developed for the hydrolysis of α-substituted p-nitrophenyl esters by directed evolution. The E values of this variant for 7 different esters was 45-276, which is a large improvement compared to 2-20 for the wild type. The broad substrate scope of this enzyme variant is of synthetic use, and hydrolysis of the tested substrates proceeded with an enantiomeric excess between 95-99%. A 30-fold increase in activity was also observed for most substrates. The developed enzyme variant shows (R)-selectivity, which is reversed compared to the wild type that is (S)-selective for most substrates.
SYNTHESE ET PROPRIETES D'UN TENSIOACTIF CATIONIQUE CHIRAL D'UN TYPE NOUVEAU, PORTEUR DE LA CHARGE SUR LE CENTRE ASYMETRIQUE
Juge, S.,Meyer, G.
, p. 959 - 964 (2007/10/02)
Surfactants in which the charge-bearing atom is chiral show catalytic properties in micellar solutions similar to those of corresponding quaternary ammonium salts.No stereoselectivity was observed in the catalytic reactions.It is clear therefore that pres
