Alicyclobacillus acidocaldarius - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Alicyclobacillus acidocaldarius

The Experts below are selected from a list of 678 Experts worldwide ranked by ideXlab platform

Alicyclobacillus acidocaldarius – Free Register to Access Experts & Abstracts

Erwin Schneider – One of the best experts on this subject based on the ideXlab platform.

Giuseppe Manco – One of the best experts on this subject based on the ideXlab platform.

  • Enlarging the substrate portfolio of the thermophilic esterase EST2 from Alicyclobacillus acidocaldarius
    Extremophiles, 2015
    Co-Authors: Angela Pennacchio, Giuseppe Manco, Luigi Mandrich, Antonio Trincone
    Abstract:

    The enzymatic regioselective hydrolysis of (a) acetylated mono- to tetrasaccharides of different nature, (b) of acetylated aryl glycosides and (c) of different acetylated nucleosides was studied enlarging the portfolio of substrates that can be employed by the thermophilic esterase EST2 from Alicyclobacillus acidocaldarius . The reactions were optimised to the extent that the amount of enzyme needed was lowered of two orders of magnitude with respect to the previously reported reactions, namely from 4000 to 40 U of enzyme per reaction. New additional solvents were screened and dramatic changes in regioselectivity were observed depending on the amount and type of solvent used. For example, in the presence of 10 % DMF, only two α- d -glucose products 6-OH and 4,6-OH (in a 76:24 ratio) were detected, whereas with 25 % DMF, at least four products of similar amount were observed. This versatility adds specific value to the biocatalyst making possible the design of biocatalytic reactions with different hydrophobic ester substrates. As an additional remarkable example, EST2 catalysed with a good yield and high regioselectivity the hydrolysis of p -nitrophenyl β- d -xylopyranoside triacetate producing only the monoacetylated derivative with acetyl group in 3-O-position, in 2 min. The results with nucleosides as substrates are particularly interesting. The peracetates of 3′,5′-di-O-acetylthymidine are converted almost quantitatively (95 %) to the monoacetylated derivative possessing free secondary OH; this regioselectivity is complementary to hydrolysis/alcoholysis reactions catalysed by CAL-B lipase or to other microbial hydrolytic biocatalysts, generally giving products with free primary OH groups. A docking analysis was undertaken with all analysed substrates suggesting a structural interpretation of the results. In most of cases, the best pose of the selected substrate was in line with the observed regioselectivity.

  • Comprehensive analysis of surface charged residues involved in thermal stability in Alicyclobacillus acidocaldarius esterase 2.
    Protein engineering design & selection : PEDS, 2012
    Co-Authors: Margherita Pezzullo, Luigi Mandrich, Pompea Del Vecchio, Mosè Rossi, Roberto Nucci, Giuseppe Manco
    Abstract:

    Here we report a comprehensive analysis through alanine-scanning mutagenesis of the contribution of surface ion pairs to the thermal stability of Alicyclobacillus acidocaldarius esterase 2 (EST2). We produced 16 single mutants, 4 double mutants corresponding to selected ion pairs R31/E118, E43/K102, R58/D130, D145/R148, 2 double mutants (R63A/R98A and E50A/D94A) involving residues of a large ion network on the protein surface and the double-mutant R98A/R148A meant to disrupt the R98 interactions within the said network and, contextually, the interaction between R148 and D145. The double-mutant E43A/E273K was obtained by chance. All selected residues were replaced with alanine except E91, which was mutated to a glycine and K102, which was changed to a glutamine. All 24 proteins were over-expressed in Escherichia coli, purified and characterized with respect to the main features. Structural stability data were compared with an in silico prediction of ΔΔG values. Our study of the individual factors involved in thermostability and their structural interpretation reveals that the great stability of this thermophilic protein can be explained by the contribution of a few residues at the protein surface.

  • Thermostable esterase 2 from Alicyclobacillus acidocaldarius as biosensor for the detection of organophosphate pesticides.
    Analytical Chemistry, 2011
    Co-Authors: Ferdinando Febbraio, Luigia Merone, Giovanni Paolo Cetrangolo, Mosè Rossi, Roberto Nucci, Giuseppe Manco
    Abstract:

    Pesticides are the plague of modern times, although much needed in agriculture, causing damage to the entire ecosystem, including humans. The high operative costs and the requirement of specialized personnel for pesticide detection, incentive to develop alternative solutions such as the set up of cheap, rapid, and simple to use biosensors. In this work, we evaluate the possibility to use the esterase 2 from Alicyclobacillus acidocaldarius as a biosensor for the detection of specific organophosphate pesticides. With the recent demonstration of the very high affinity of esterase 2 toward paraoxon, a more complete analysis on the detection methods in water as well as in purposely contaminated fruit juices was carried out. The inhibitory effects of a wide range of other pesticides on esterase 2 were investigated, showing a better selectivity with respect to nonspecific reaction of acethylcholinesterases, the main target of organophosphate pesticides. The applied methodology allowed one to detect 2.75 × 10−3 p…

Mosè Rossi – One of the best experts on this subject based on the ideXlab platform.

  • Comprehensive analysis of surface charged residues involved in thermal stability in Alicyclobacillus acidocaldarius esterase 2.
    Protein engineering design & selection : PEDS, 2012
    Co-Authors: Margherita Pezzullo, Luigi Mandrich, Pompea Del Vecchio, Mosè Rossi, Roberto Nucci, Giuseppe Manco
    Abstract:

    Here we report a comprehensive analysis through alanine-scanning mutagenesis of the contribution of surface ion pairs to the thermal stability of Alicyclobacillus acidocaldarius esterase 2 (EST2). We produced 16 single mutants, 4 double mutants corresponding to selected ion pairs R31/E118, E43/K102, R58/D130, D145/R148, 2 double mutants (R63A/R98A and E50A/D94A) involving residues of a large ion network on the protein surface and the double-mutant R98A/R148A meant to disrupt the R98 interactions within the said network and, contextually, the interaction between R148 and D145. The double-mutant E43A/E273K was obtained by chance. All selected residues were replaced with alanine except E91, which was mutated to a glycine and K102, which was changed to a glutamine. All 24 proteins were over-expressed in Escherichia coli, purified and characterized with respect to the main features. Structural stability data were compared with an in silico prediction of ΔΔG values. Our study of the individual factors involved in thermostability and their structural interpretation reveals that the great stability of this thermophilic protein can be explained by the contribution of a few residues at the protein surface.

  • Thermostable esterase 2 from Alicyclobacillus acidocaldarius as biosensor for the detection of organophosphate pesticides.
    Analytical Chemistry, 2011
    Co-Authors: Ferdinando Febbraio, Luigia Merone, Giovanni Paolo Cetrangolo, Mosè Rossi, Roberto Nucci, Giuseppe Manco
    Abstract:

    Pesticides are the plague of modern times, although much needed in agriculture, causing damage to the entire ecosystem, including humans. The high operative costs and the requirement of specialized personnel for pesticide detection, incentive to develop alternative solutions such as the set up of cheap, rapid, and simple to use biosensors. In this work, we evaluate the possibility to use the esterase 2 from Alicyclobacillus acidocaldarius as a biosensor for the detection of specific organophosphate pesticides. With the recent demonstration of the very high affinity of esterase 2 toward paraoxon, a more complete analysis on the detection methods in water as well as in purposely contaminated fruit juices was carried out. The inhibitory effects of a wide range of other pesticides on esterase 2 were investigated, showing a better selectivity with respect to nonspecific reaction of acethylcholinesterases, the main target of organophosphate pesticides. The applied methodology allowed one to detect 2.75 × 10−3 p…

  • Irreversible inhibition of the thermophilic esterase EST2 from Alicyclobacillus acidocaldarius
    Extremophiles, 2008
    Co-Authors: Ferdinando Febbraio, Luigi Mandrich, Luigia Merone, Mosè Rossi, Roberto Nucci, Sandro Esposito D’andrea, Giuseppe Manco
    Abstract:

    Kinetic studies of irreversible inhibition in recent years have received growing attention owing to their relevance to problems of basic scientific interest as well as to their practical importance. Our studies have been devoted to the characterization of the effects that well-known acetylcholinesterase irreversible inhibitors exert on a carboxylesterase (EST2) from the thermophilic eubacterium Alicyclobacillus acidocaldarius . In particular, sulfonyl inhibitors and the organophosphorous insecticide diethyl- p -nitrophenyl phosphate (paraoxon) have been studied. The incubation of EST2 with sulfonyl inhibitors resulted in a time-dependent inactivation according to a pseudo-first-order kinetics. On the other hand, the EST2 inactivation process elicited by paraoxon, being the inhibition reaction completed immediately after the inhibitor addition, cannot be described as a pseudo-first-order kinetics but is better considered as a high affinity inhibition. The values of apparent rate constants for paraoxon inactivation were determined by monitoring the enzyme/substrate reaction in the presence of the inhibitor, and were compared with those of the sulfonyl inhibitors. The protective effect afforded by a competitive inhiinhibitor on the EST2 irreversible inhibition, and the reactivation of a complex enzyme/irreversible-inhibitor by hydroxylamine and 2-PAM, were also investigated. The data have been discussed in the light of the recently described dual substrate binding mode of EST2, considering that the irreversible inhibitors employed were able to discriminate between the two different binding sites.

Karl Poralla – One of the best experts on this subject based on the ideXlab platform.

Mathias Sprinzl – One of the best experts on this subject based on the ideXlab platform.