Khusnutdinova AN

References (5)

Title : Thermophilic Carboxylesterases from Hydrothermal Vents of the Volcanic Island of Ischia Active on Synthetic and Biobased Polymers and Mycotoxins - Distaso_2023_Appl.Environ.Microbiol__e0170422
Author(s) : Distaso MA , Chernikova TN , Bargiela R , Coscolin C , Stogios P , Gonzalez-Alfonso JL , Lemak S , Khusnutdinova AN , Plou FJ , Evdokimova E , Savchenko A , Lunev EA , Yakimov MM , Golyshina OV , Ferrer M , Yakunin AF , Golyshin PN
Ref : Applied Environmental Microbiology , :e0170422 , 2023
Abstract : Hydrothermal vents are geographically widespread and host microorganisms with robust enzymes useful in various industrial applications. We examined microbial communities and carboxylesterases of two terrestrial hydrothermal vents of the volcanic island of Ischia (Italy) predominantly composed of Firmicutes, Proteobacteria, and Bacteroidota. High-temperature enrichment cultures with the polyester plastics polyhydroxybutyrate and polylactic acid (PLA) resulted in an increase of Thermus and Geobacillus species and to some extent Fontimonas and Schleiferia species. The screening at 37 to 70 degreesC of metagenomic fosmid libraries from above enrichment cultures identified three hydrolases (IS10, IS11, and IS12), all derived from yet-uncultured Chloroflexota and showing low sequence identity (33 to 56%) to characterized enzymes. Enzymes expressed in Escherichia coli exhibited maximal esterase activity at 70 to 90 degreesC, with IS11 showing the highest thermostability (90% activity after 20-min incubation at 80 degreesC). IS10 and IS12 were highly substrate promiscuous and hydrolyzed all 51 monoester substrates tested. Enzymes were active with PLA, polyethylene terephthalate model substrate, and mycotoxin T-2 (IS12). IS10 and IS12 had a classical alpha/beta-hydrolase core domain with a serine hydrolase catalytic triad (Ser155, His280, and Asp250) in their hydrophobic active sites. The crystal structure of IS11 resolved at 2.92 A revealed the presence of a N-terminal beta-lactamase-like domain and C-terminal lipocalin domain. The catalytic cleft of IS11 included catalytic Ser68, Lys71, Tyr160, and Asn162, whereas the lipocalin domain enclosed the catalytic cleft like a lid and contributed to substrate binding. Our study identified novel thermotolerant carboxylesterases with a broad substrate range, including polyesters and mycotoxins, for potential applications in biotechnology. IMPORTANCE High-temperature-active microbial enzymes are important biocatalysts for many industrial applications, including recycling of synthetic and biobased polyesters increasingly used in textiles, fibers, coatings and adhesives. Here, we identified three novel thermotolerant carboxylesterases (IS10, IS11, and IS12) from high-temperature enrichment cultures from Ischia hydrothermal vents and incubated with biobased polymers. The identified metagenomic enzymes originated from uncultured Chloroflexota and showed low sequence similarity to known carboxylesterases. Active sites of IS10 and IS12 had the largest effective volumes among the characterized prokaryotic carboxylesterases and exhibited high substrate promiscuity, including hydrolysis of polyesters and mycotoxin T-2 (IS12). Though less promiscuous than IS10 and IS12, IS11 had a higher thermostability with a high temperature optimum (80 to 90 degreesC) for activity and hydrolyzed polyesters, and its crystal structure revealed an unusual lipocalin domain likely involved in substrate binding. The polyesterase activity of these enzymes makes them attractive candidates for further optimization and potential application in plastics recycling.
ESTHER : Distaso_2023_Appl.Environ.Microbiol__e0170422
PubMedSearch : Distaso_2023_Appl.Environ.Microbiol__e0170422
PubMedID: 36719236
Gene_locus related to this paper: 9bact-estC55.8n1 , 9bact-IS10

Title : Harnessing extremophilic carboxylesterases for applications in polyester depolymerisation and plastic waste recycling - Williams_2023_Essays.Biochem__
Author(s) : Williams GB , Ma H , Khusnutdinova AN , Yakunin AF , Golyshin PN
Ref : Essays Biochem , : , 2023
Abstract : The steady growth in industrial production of synthetic plastics and their limited recycling have resulted in severe environmental pollution and contribute to global warming and oil depletion. Currently, there is an urgent need to develop efficient plastic recycling technologies to prevent further environmental pollution and recover chemical feedstocks for polymer re-synthesis and upcycling in a circular economy. Enzymatic depolymerization of synthetic polyesters by microbial carboxylesterases provides an attractive addition to existing mechanical and chemical recycling technologies due to enzyme specificity, low energy consumption, and mild reaction conditions. Carboxylesterases constitute a diverse group of serine-dependent hydrolases catalysing the cleavage and formation of ester bonds. However, the stability and hydrolytic activity of identified natural esterases towards synthetic polyesters are usually insufficient for applications in industrial polyester recycling. This necessitates further efforts on the discovery of robust enzymes, as well as protein engineering of natural enzymes for enhanced activity and stability. In this essay, we discuss the current knowledge of microbial carboxylesterases that degrade polyesters (polyesterases) with focus on polyethylene terephthalate (PET), which is one of the five major synthetic polymers. Then, we briefly review the recent progress in the discovery and protein engineering of microbial polyesterases, as well as developing enzyme cocktails and secreted protein expression for applications in the depolymerisation of polyester blends and mixed plastics. Future research aimed at the discovery of novel polyesterases from extreme environments and protein engineering for improved performance will aid developing efficient polyester recycling technologies for the circular plastics economy.
ESTHER : Williams_2023_Essays.Biochem__
PubMedSearch : Williams_2023_Essays.Biochem__
PubMedID: 37334661

Title : Structural insights into hydrolytic defluorination of difluoroacetate by microbial fluoroacetate dehalogenases - Khusnutdinova_2023_FEBS.J_290_4966
Author(s) : Khusnutdinova AN , Batyrova KA , Brown G , Fedorchuk T , Chai YS , Skarina T , Flick R , Petit AP , Savchenko A , Stogios P , Yakunin AF
Ref : Febs J , 290 :4966 , 2023
Abstract : Fluorine forms the strongest single bond to carbon with the highest bond dissociation energy among natural products. However, fluoroacetate dehalogenases (FADs) have been shown to hydrolyze this bond in fluoroacetate under mild reaction conditions. Furthermore, two recent studies demonstrated that the FAD RPA1163 from Rhodopseudomonas palustris can also accept bulkier substrates. In this study, we explored the substrate promiscuity of microbial FADs and their ability to defluorinate polyfluorinated organic acids. Enzymatic screening of eight purified dehalogenases with reported fluoroacetate defluorination activity revealed significant hydrolytic activity against difluoroacetate in three proteins. Product analysis using liquid chromatography-mass spectrometry identified glyoxylic acid as the final product of enzymatic DFA defluorination. The crystal structures of DAR3835 from Dechloromonas aromatica and NOS0089 from Nostoc sp. were determined in the apo-state along with the DAR3835 H274N glycolyl intermediate. Structure-based site-directed mutagenesis of DAR3835 demonstrated a key role for the catalytic triad and other active site residues in the defluorination of both fluoroacetate and difluoroacetate. Computational analysis of the dimer structures of DAR3835, NOS0089, and RPA1163 indicated the presence of one substrate access tunnel in each protomer. Moreover, protein-ligand docking simulations suggested similar catalytic mechanisms for the defluorination of both fluoroacetate and difluoroacetate, with difluoroacetate being defluorinated via two consecutive defluorination reactions producing glyoxylate as the final product. Thus, our findings provide molecular insights into substrate promiscuity and catalytic mechanism of FADs, which are promising biocatalysts for applications in synthetic chemistry and bioremediation of fluorochemicals.
ESTHER : Khusnutdinova_2023_FEBS.J_290_4966
PubMedSearch : Khusnutdinova_2023_FEBS.J_290_4966
PubMedID: 37437000
Gene_locus related to this paper: anasp-ALR0039 , decar-q479b8

Title : Screening and Characterization of Novel Polyesterases from Environmental Metagenomes with High Hydrolytic Activity against Synthetic Polyesters - Hajighasemi_2018_Environ.Sci.Technol_52_12388
Author(s) : Hajighasemi M , Tchigvintsev A , Nocek B , Flick R , Popovic A , Hai T , Khusnutdinova AN , Brown G , Xu X , Cui H , Anstett J , Chernikova TN , Bruls T , Le Paslier D , Yakimov MM , Joachimiak A , Golyshina OV , Savchenko A , Golyshin PN , Edwards EA , Yakunin AF
Ref : Environ Sci Technol , 52 :12388 , 2018
Abstract : The continuous growth of global plastics production, including polyesters, has resulted in increasing plastic pollution and subsequent negative environmental impacts. Therefore, enzyme-catalyzed depolymerization of synthetic polyesters as a plastics recycling approach has become a focus of research. In this study, we screened over 200 purified uncharacterized hydrolases from environmental metagenomes and sequenced microbial genomes and identified at least 10 proteins with high hydrolytic activity against synthetic polyesters. These include the metagenomic esterases MGS0156 and GEN0105, which hydrolyzed polylactic acid (PLA), polycaprolactone, as well as bis(benzoyloxyethyl)-terephthalate. With solid PLA as a substrate, both enzymes produced a mixture of lactic acid monomers, dimers, and higher oligomers as products. The crystal structure of MGS0156 was determined at 1.95 A resolution and revealed a modified alpha/beta hydrolase fold, with a lid domain and highly hydrophobic active site. Mutational studies of MGS0156 identified the residues critical for hydrolytic activity against both polyester and monoester substrates, with two-times higher polyesterase activity in the MGS0156 L169A mutant protein. Thus, our work identified novel, highly active polyesterases in environmental metagenomes and provided molecular insights into their activity, thereby augmenting our understanding of enzymatic polyester hydrolysis.
ESTHER : Hajighasemi_2018_Environ.Sci.Technol_52_12388
PubMedSearch : Hajighasemi_2018_Environ.Sci.Technol_52_12388
PubMedID: 30284819
Gene_locus related to this paper: 9zzzz-a0a0g3fj39 , 9zzzz-a0a0g3fj48 , 9zzzz-A0A0G3FEJ8 , 9bact-a4uz10

Title : Activity screening of environmental metagenomic libraries reveals novel carboxylesterase families - Popovic_2017_Sci.Rep_7_44103
Author(s) : Popovic A , Hai T , Tchigvintsev A , Hajighasemi M , Nocek B , Khusnutdinova AN , Brown G , Glinos J , Flick R , Skarina T , Chernikova TN , Yim V , Bruls T , Paslier DL , Yakimov MM , Joachimiak A , Ferrer M , Golyshina OV , Savchenko A , Golyshin PN , Yakunin AF
Ref : Sci Rep , 7 :44103 , 2017
Abstract : Metagenomics has made accessible an enormous reserve of global biochemical diversity. To tap into this vast resource of novel enzymes, we have screened over one million clones from metagenome DNA libraries derived from sixteen different environments for carboxylesterase activity and identified 714 positive hits. We have validated the esterase activity of 80 selected genes, which belong to 17 different protein families including unknown and cyclase-like proteins. Three metagenomic enzymes exhibited lipase activity, and seven proteins showed polyester depolymerization activity against polylactic acid and polycaprolactone. Detailed biochemical characterization of four new enzymes revealed their substrate preference, whereas their catalytic residues were identified using site-directed mutagenesis. The crystal structure of the metal-ion dependent esterase MGS0169 from the amidohydrolase superfamily revealed a novel active site with a bound unknown ligand. Thus, activity-centered metagenomics has revealed diverse enzymes and novel families of microbial carboxylesterases, whose activity could not have been predicted using bioinformatics tools.
ESTHER : Popovic_2017_Sci.Rep_7_44103
PubMedSearch : Popovic_2017_Sci.Rep_7_44103
PubMedID: 28272521
Gene_locus related to this paper: 9zzzz-a0a0g3fj39 , 9zzzz-a0a0g3fj48 , 9zzzz-A0A0G3FEJ8