Asther M

References (5)

Title : Gene overexpression and biochemical characterization of the biotechnologically relevant chlorogenic acid hydrolase from Aspergillus niger - Benoit_2007_Appl.Environ.Microbiol_73_5624
Author(s) : Benoit I , Asther M , Bourne Y , Navarro D , Canaan S , Lesage-Meessen L , Herweijer M , Coutinho PM , Record E
Ref : Applied Environmental Microbiology , 73 :5624 , 2007
Abstract : The full-length gene that encodes the chlorogenic acid hydrolase from Aspergillus niger CIRM BRFM 131 was cloned by PCR based on the genome of the strain A. niger CBS 513.88. The complete gene consists of 1,715 bp and codes for a deduced protein of 512 amino acids with a molecular mass of 55,264 Da and an acidic pI of 4.6. The gene was successfully cloned and overexpressed in A. niger to yield 1.25 g liter(-1), i.e., 330-fold higher than the production of wild-type strain A. niger CIRM BRFM131. The histidine-tagged recombinant ChlE protein was purified to homogeneity via a single chromatography step, and its main biochemical properties were characterized. The molecular size of the protein checked by mass spectroscopy was 74,553 Da, suggesting the presence of glycosylation. ChlE is assembled in a tetrameric form with several acidic isoforms with pIs of around 4.55 and 5.2. Other characteristics, such as optimal pH and temperature, were found to be similar to those determined for the previously characterized chlorogenic acid hydrolase of A. niger CIRM BRFM 131. However, there was a significant temperature stability difference in favor of the recombinant protein. ChlE exhibits a catalytic efficiency of 12.5 x 10(6) M(-1) s(-1) toward chlorogenic acid (CGA), and its ability to release caffeic acid from CGA present in agricultural by-products such as apple marc and coffee pulp was clearly demonstrated, confirming the high potential of this enzyme.
ESTHER : Benoit_2007_Appl.Environ.Microbiol_73_5624
PubMedSearch : Benoit_2007_Appl.Environ.Microbiol_73_5624
PubMedID: 17630312
Gene_locus related to this paper: aspnc-a2qn56

Title : Respective importance of protein folding and glycosylation in the thermal stability of recombinant feruloyl esterase A - Benoit_2006_FEBS.Lett_580_5815
Author(s) : Benoit I , Asther M , Sulzenbacher G , Record E , Marmuse L , Parsiegla G , Gimbert I , Bignon C
Ref : FEBS Letters , 580 :5815 , 2006
Abstract : The thermal stability of four molecular forms (native, refolded, glycosylated, non-glycosylated) of feruloyl esterase A (FAEA) was studied. From the most to the least thermo-resistant, the four molecular species ranked as follows: (i) glycosylated form produced native, (ii) non-glycosylated form produced native, (iii) non-glycosylated form produced as inclusion bodies and refolded, and (iv) glycosylated form produced native chemically denatured and then refolded. On the basis of these results and of crystal structure data, we discuss the respective importance of protein folding and glycosylation in the thermal stability of recombinant FAEA.
ESTHER : Benoit_2006_FEBS.Lett_580_5815
PubMedSearch : Benoit_2006_FEBS.Lett_580_5815
PubMedID: 17027758
Gene_locus related to this paper: aspni-FAEA

Title : Tracking the connection between evolutionary and functional shifts using the fungal lipase\/feruloyl esterase A family - Levasseur_2006_BMC.Evol.Biol_6_92
Author(s) : Levasseur A , Gouret P , Lesage-Meessen L , Asther M , Record E , Pontarotti P
Ref : BMC Evol Biol , 6 :92 , 2006
Abstract : BACKGROUND: There have been many claims of adaptive molecular evolution, but what role does positive selection play in functional divergence? The aim of this study was to test the relationship between evolutionary and functional shifts with special emphasis on the role of the environment. For this purpose, we studied the fungal lipase/feruloyl esterase A family, whose functional diversification makes it a very promising candidate.
RESULTS: The results suggested functional shift following a duplication event where neofunctionalisation of feruloyl esterase A had occurred with conservation of the ancestral lipase function. Evolutionary shift was detected using the branch-site model for testing positive selection on individual codons along specific lineages. Positively selected amino acids were detected. Furthermore, biological data obtained from site-directed mutagenesis experiments clearly demonstrated that certain amino acids under positive selection were involved in the functional shift. We reassessed evolutionary history in terms of environmental response, and hypothesized that environmental changes such as colonisation by terrestrial plants might have driven adaptation by functional diversification in Euascomycetes (Aspergilli), thus conferring a selective advantage on this group. CONCLUSION: The results reported here illustrate a rare example of connection between fundamental events in molecular evolution. We demonstrated an unequivocal connection between evolutionary and functional shifts, which led us to conclude that these events were probably linked to environmental change.
ESTHER : Levasseur_2006_BMC.Evol.Biol_6_92
PubMedSearch : Levasseur_2006_BMC.Evol.Biol_6_92
PubMedID: 17092334

Title : Feruloyl esterases as a tool for the release of phenolic compounds from agro-industrial by-products - Benoit_2006_Carbohydr.Res_341_1820
Author(s) : Benoit I , Navarro D , Marnet N , Rakotomanomana N , Lesage-Meessen L , Sigoillot JC , Asther M
Ref : Carbohydr Res , 341 :1820 , 2006
Abstract : Agro-industrial by-products are a potential source of added-value phenolic acids with promising applications in the food and pharmaceutical industries. Here two purified feruloyl esterases from Aspergillus niger, FAEA and FAEB were tested for their ability to release phenolic acids such as caffeic acid, p-coumaric acid and ferulic acid from coffee pulp, apple marc and wheat straw. Their hydrolysis activity was evaluated and compared with their action on maize bran and sugar beet pulp. The specificity of both enzymes against natural and synthetic substrates was evaluated; particular attention was paid to quinic esters and lignin monomers. The efficiency of both enzymes on model substrates was studied. We show the ability of these enzymes to hydrolyze quinic esters and ester linkages between phenolic acids and lignin monomer.
ESTHER : Benoit_2006_Carbohydr.Res_341_1820
PubMedSearch : Benoit_2006_Carbohydr.Res_341_1820
PubMedID: 16697997
Gene_locus related to this paper: myctt-faeb , aspni-FAEA , myctt-g2qmb4 , theto-FaeB1 , 9euro-g4xkn5

Title : Homologous expression of the feruloyl esterase B gene from Aspergillus niger and characterization of the recombinant enzyme - Levasseur_2004_Protein.Expr.Purif_37_126
Author(s) : Levasseur A , Benoit I , Asther M , Record E
Ref : Protein Expr Purif , 37 :126 , 2004
Abstract : The faeB gene encoding the feruloyl esterase B (FAEB) was isolated from Aspergillus niger BRFM131 genomic DNA. The faeB gene, with additional sequence coding for a C-terminal histidine tag, was inserted into an expression vector under the control of the gpd promoter and trpC terminator and expressed in a protease deficient A. niger strain. Homologous overproduction allows to reach an esterase activity of 18 nkat mL(-1) against MCA as substrate. The improvement factor was 16-fold higher as compared to the production level obtained with non-transformed A. niger strain induced by sugar beet pulp. The corresponding secretion yield was estimated to be around 100 mg L(-1). Recombinant FAEB was purified 14.6-fold to homogeneity from an 8-day-old culture by a single affinity chromatographic step with a recovery of 64%. SDS-PAGE revealed a single band with a molecular mass of 75 kDa, while under non-denatured conditions, native enzyme has a molecular mass of around 150 kDa confirming that the recombinant FAEB is a homodimer. The recombinant and native FAEB have the same characteristics concerning temperature and pH optima, i.e., 50 degrees C and 6, respectively. In addition, the recombinant FAEB was determined to be quite stable up to 50 degrees C for 120 min. Kinetic constants for MCA, MpCA, and chlorogenic acid (5-O-caffeoyl quinic acid) were as follows: Km: 0.13, 0.029, and 0.16 mM and Vmax: 1101, 527.6, and 28.3 nkat mg(-1), respectively. This is the first report on the homologous overproduction of feruloyl esterase B in A. niger.
ESTHER : Levasseur_2004_Protein.Expr.Purif_37_126
PubMedSearch : Levasseur_2004_Protein.Expr.Purif_37_126
PubMedID: 15294290
Gene_locus related to this paper: aspng-faeb