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1.
Biochimie ; 216: 83-89, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37820990

RESUMO

Xylanases are used in several industrial applications, such as feed additives, the bleaching of pulp and paper, and the production of bread, food, and drinks. Xylanases are required to remain active after heat treatment at 80-90 °C for 30 s to several minutes due to the conditions of feed pelleting. Also, xylanases need to be active at 60-70 °C for several hours while bleaching of pulp and paper or manufacturing of bread, food, and drinks is performed. Xylanases of the glycoside hydrolase family GH10 are good candidates for application in such processes because of their high thermostability and, in particular, as feed additives because of their insensitivity to protein inhibitors in cereal feeds. In the study, the thermostability of GH10 xylanase E from Penicillium canescens was improved to reach a half-inactivation period of 2 min at 80 °C compared to 21 s for the wild-type enzyme (WT). Enzymatic activity was increased by 22-48 % at 40-70 °C, which improved the action of the enzyme as a feed additive in the gastric system of animals and during bleaching of pulp and paper. Molecular dynamics simulations demonstrated lower flexibility of the tertiary structure of the engineered enzyme at elevated temperatures compared to WT. The residues W113, Q116, W313, and W321 in the (-1) and (-2) subsites for the substrate binding were less flexible. In the simulations, the engineered enzyme had a comparable content of α-helixes, 310-helixes, ß-sheets, and ß-bridges as WT, but a lower content of coils and a higher content of ß-turns.


Assuntos
Endo-1,4-beta-Xilanases , Penicillium , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/metabolismo , Temperatura , Estabilidade Enzimática
2.
Res Microbiol ; 175(4): 104178, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38160731

RESUMO

In this study, CRISPR/Cas9 genome editing was used to knockout the bgl2 gene encoding intracellular ß-glucosidase filamentous fungus Penicillium verruculosum. This resulted in a dramatic reduction of secretion of cellulolytic enzymes. The study of P. verruculosum Δbgl2 found that the transcription of the cbh1 gene, which encodes cellobiohydrolase 1, was impaired when induced by cellobiose and cellotriose. However, the transcription of the cbh1 gene remains at level of the host strain when induced by gentiobiose. This implies that gentiobiose is the true inducer of the cellulolytic response in P. verruculosum, in contrast to Neurospora crassa where cellobiose acts as an inducer.


Assuntos
Penicillium , beta-Glucosidase , Penicillium/genética , Penicillium/enzimologia , beta-Glucosidase/metabolismo , beta-Glucosidase/genética , Regulação Fúngica da Expressão Gênica , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Celulose/metabolismo , Celobiose/metabolismo , Sistemas CRISPR-Cas , Técnicas de Inativação de Genes , Neurospora crassa/genética , Neurospora crassa/enzimologia , Celulose 1,4-beta-Celobiosidase/metabolismo , Celulose 1,4-beta-Celobiosidase/genética , Edição de Genes
3.
J Bioinform Comput Biol ; 21(2): 2330001, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36884016

RESUMO

Thermostability of cellulases can be increased through amino acid substitutions and by protein engineering with predictors of protein thermostability. We have carried out a systematic analysis of the performance of 18 predictors for the engineering of cellulases. The predictors were PoPMuSiC, HoTMuSiC, I-Mutant 2.0, I-Mutant Suite, PremPS, Hotspot, Maestroweb, DynaMut, ENCoM ([Formula: see text] and [Formula: see text], mCSM, SDM, DUET, RosettaDesign, Cupsat (thermal and denaturant approaches), ConSurf, and Voronoia. The highest values of accuracy, F-measure, and MCC were obtained for DynaMut, SDM, RosettaDesign, and PremPS. A combination of the predictors provided an improvement in the performance. F-measure and MCC were improved by 14% and 28%, respectively. Accuracy and sensitivity were also improved by 9% and 20%, respectively, compared to the maximal values of single predictors. The reported values of the performance of the predictors and their combination may aid research in the engineering of thermostable cellulases as well as the further development of thermostability predictors.


Assuntos
Celulases , Celulases/genética , Celulases/química , Celulases/metabolismo , Estabilidade Enzimática , Engenharia de Proteínas , Substituição de Aminoácidos , Temperatura
4.
Bone Marrow Transplant ; 58(3): 257-264, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36450828

RESUMO

In the early randomized trials the efficacy of calcineurin inhibitors (CNI) in the treatment of graft-versus-host disease (GVHD) was comparable to corticosteroids (CS), but these results became obsolete with the introduction of CNIs in prophylaxis. Recently several effective CNI-free GVHD prophylaxis regimens were introduced based on posttransplantation cyclophosphamide (PTCY) and αß ex vivo T-cell depletion (αß-TCD). Among patients treated under these protocols 34 patients with grade II-IV acute (aGVHD) and 40 with moderate and severe chronic (cGVHD) disease were treated with CNIs or other CS-free regimens as the first line. Overall response rate (ORR) was significantly higher in cGVHD than in aGVHD: 80% (95% CI 68-92) vs 47% (95% CI 30-64%), p = 0.0031. In aGVHD it was almost completely restricted to isolated stage III skin GVHD. In cGVHD patients with moderate disease ORR was higher than in severe: 96% (95% CI 88-100%) vs 56% (95%CI 32-81%), p = 0.0022. Two-year overall survival was 76% (95% CI 58-87%) in aGVHD and 95% (95% CI 81-99%) in cGVHD. Failure-free survival was 21% (95% CI 9-37%) in aGVHD and 81% (95% CI 64-91%) in cGVHD. Patients responding to steroid-free regimens had lower use of systemic antibiotics (p = 0.0095), antifungals (p = 0.0319) and antivirals (p < 0.0001).


Assuntos
Síndrome de Bronquiolite Obliterante , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Humanos , Ciclofosfamida/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/métodos , Transplante de Medula Óssea/efeitos adversos , Inibidores de Calcineurina/uso terapêutico , Corticosteroides/uso terapêutico , Doença Aguda
5.
J Mol Graph Model ; 119: 108381, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36473387

RESUMO

Exo-inulinases are applied in inulin hydrolysis and production of feed additives and need to be stable at temperatures of 60-95 °C. Aspergillus awamori exo-inulinase Inu1 is considerably thermostable, with a Tm of 73.2 °C. However, the thermostability of the enzyme should be improved. A single substitution G338A in α-helix in the active center of the enzyme provided a 3.5 °C improvement in Tm. The time of half-life at 70 °C and 80 °C was increased in 5.7- and 2.7-times, respectively, compared to wild-type. Molecular dynamics simulations demonstrated that the substitution G338A caused a decrease in RMSF not only for the α-helix 337-YAANI-341, but also for the catalytically active residues D41 and E241 and the amino acid residues forming the cleft of the active center. Calculations with Constraint Network Analysis for the variant G338A showed the increase in the stability of intramolecular clusters.


Assuntos
Aspergillus , Glicosídeo Hidrolases , Conformação Proteica em alfa-Hélice , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/química , Aspergillus/genética , Estabilidade Enzimática
6.
Biochem Biophys Res Commun ; 634: 55-61, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-36228545

RESUMO

Aspergillus niger ATCC 10864 phytase A was produced in Penicillium verruculosum. The enzyme was found to have two pH optima of 2.5 and 5.0, as well as a T-optimum of 50-55 °C. Two amino acid substitutions, A76M and S265P, were designed for improvement in thermostability, and two more, N300K and D363N, were designed for improvement in enzyme activity. The most thermostable variant, S265P, was characterized by a 3.8-fold increase in time of half-life at 55 °C and a 1.2-fold increase in residual activity at 90 °C compared to the wild-type. The most active variant, D363N, was 1.7-times more active at 40 °C and retained 1.3-times higher residual activity at 90 °C compared to the wild-type. The obtained results revealed the importance of substitutions with proline in α-helixes for the thermostability improvement of phytases. Also, the importance of sequence motif 361HDN363 was demonstrated with relevance to values of catalytic parameters.


Assuntos
6-Fitase , 6-Fitase/genética , 6-Fitase/química , 6-Fitase/metabolismo , Aspergillus niger , Estabilidade Enzimática , Concentração de Íons de Hidrogênio
7.
Enzyme Microb Technol ; 152: 109938, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34753033

RESUMO

Hydrolytic enzymes are highly demanded in the industry. Thermostability is an important property of enzymes that affects the economic costs of the industrial processes. The rational design of GH10 xylanase E (XylE) Penicillium canescens for the thermostability improvement was directed by ΔΔG calculations and structure analysis. Amino acid substitutions with stabilizing values of ΔΔG and providing an increase in side-chain volume of buried residues were performed experimentally. From the six designed substitutions, four substitutions appeared to be stabilizing, one - destabilizing, and one - neutral. For the improved XylE variants, values of Tm were increased by 1.1-3.1 °C, and times of half-life at 70 °C were increased in 1.3-1.7-times. Three of the four stabilizing substitutions were located in the N- or the C-terminus region. This highlights the importance of N- and C-terminus for the thermostability of GH10 xylanases and also enzymes with (ß/α)8 TIM barrel type of structure. The criteria of stabilizing values of ΔΔG and increased side-chain volume of buried residues for selection of substitutions may be applied in the rational design for thermostability improvement.


Assuntos
Penicillium , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Estabilidade Enzimática , Penicillium/genética , Penicillium/metabolismo , Temperatura
8.
Pharmaceuticals (Basel) ; 14(8)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34451905

RESUMO

Chronic graft versus host disease (cGVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). It significantly decreases survival and quality of life. The present study demonstrates retrospective data on extracorporeal photopheresis (ECP) in children with cGVHD. A total of 42 children with steroid-refractory cGVHD were enrolled in the study. The majority of patients had acute leukemia (n = 32, 76%). All patients received ECP as second (n = 18, 43%) or third (n = 24, 57%) line of therapy. Initial ECP schedule consisted of bimonthly regimen for two consecutive days with possibility of further tapering according to response. Any concurrent treatment administered before ECP could be continued if considered necessary. Complete response to ECP was registered in seven (17%) patients and partial response in 24 (57%). Overall response according to organ involvement was as follows: skin (n = 24, 75%), mucous membranes (n = 16, 73%), liver (n = 8, 80%), gut (n = 4, 80%), lungs (n = 2, 22%) and joints (n = 2, 67%). Five-year overall, progression-free and failure-free survival was 57%, 56% and 30%, respectively. Non-relapse mortality at 5 years was 14%. We didn't observe any clinically significant complications in children that could be attributed to the procedure. ECP remains important and safe treatment option in children with cGVHD.

9.
Transplant Cell Ther ; 27(7): 601.e1-601.e7, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33845259

RESUMO

The prognosis of acute leukemia refractory to induction chemotherapy or immunotherapy is dismal. Salvage allogeneic hematopoietic stem cell transplantation (HSCT) is widely used option for these patients, but only 10% to 15% of patients are cured by the procedure. Preclinical studies indicate that substitution of post-transplantation cyclophosphamide with bendamustine (PTB) in a prophylaxis regimen may be associated with an augmented graft-versus-leukemia (GVL) reaction. The aim of this study was to establish the optimal dose of PTB and evaluate the antileukemic effect of HSCT with this type of graft-versus-host disease (GVHD) prophylaxis. In the prospective trial (NCT02799147), PTB was administered in doses of 140, 100, and 70 mg/m2 on days +3 and +4. Myeloablative conditioning with fludarabine and oral busulfan was provided to all patients. The first 12 patients received single-agent PTB, and subsequent patients received combination therapy with tacrolimus and mycophenolate mofetil (MMF). Inclusion criteria were acute myelogenous leukemia (AML) or acute lymphoblastic leukemia (ALL) refractory to at least one induction course of chemotherapy or target therapy and ≥5% clonal blasts in the bone marrow. The study cohort comprised 22 patients with AML and 5 with ALL. Seven patients were enrolled in the 140 mg/m2 group (due to a stopping rule), and 10 each were enrolled in the 100 mg/m2 and 70 mg/m2 groups. Primary refractory disease was documented in 41% of the patients, and secondary refractory was documented in 59%. The median blast count in the bone marrow at the start of the conditioning was 18% (range, 6% to 97%). Transplantation was performed with a matched sibling donor in 5 patients, a matched or mismatched unrelated donor in 15, and a haploidentical donor in 7. Engraftment was documented in 93% of the patients, including 89% with complete remission and 63% without measurable residual disease. After PTB prophylaxis, we observed an unusual complication, a cytokine release syndrome (CRS), in 70% of the patients, including grade 3 to 5 CRS in 44%. The most frequent clinical symptoms included high fever in 67% of patients, abnormal liver function tests in 67%, pancreatitis in 63%, skin vasculitis in 56%, enterocolitis in 48%, inflammation of oral mucosa in 37%, disseminated intravascular coagulation in 37%, and central nervous system toxicity in 26%. The development of CRS was associated with use of an HLA-mismatched donor (75% versus 20%; P = .0043). Classic acute GVHD was documented in 44% of the patients. Grade II-IV acute GVHD was associated with grade 3 to 5 CRS (67% versus 25%; P = .031). Moderate and severe chronic GVHD in the 100-day survivors were more often observed after single-agent PTB than after the combination immunosuppression (100% versus 18%; P = .002). A relatively low relapse rate was observed for this patient population. Three-year overall survival was 28% (95% confidence interval [CI], 13% to 46%), and event-free survival was 29% (95% CI, 13% to 46%). Nonrelapse mortality was 46% (95% CI, 25% to 64%), and the cumulative incidence of relapse was 26% (95% CI, 11% to 44%). No relapses were documented after day +100. There were no statistically significant differences among the dose groups (P = .3481); however, survival was higher in the 100 mg/kg group. Survival was higher in patients with AML compared with those with ALL (35% versus 0%; P = .0157). PTB represents a promising option to augment the GVL effect in refractory AML; however, the high CRS-associated mortality necessitates additional studies to reduce the risk of this complication. Thus, routine clinical application of PTB cannot be currently recommended. Combination immunosuppression with tacrolimus and MMF partially ameliorates these complications, at least in the setting of HLA-matched allografts. Biological mechanisms of CRS and GVL after PTB require further elucidation.


Assuntos
Doença Enxerto-Hospedeiro , Cloridrato de Bendamustina/efeitos adversos , Bussulfano , Doença Enxerto-Hospedeiro/prevenção & controle , Humanos , Estudos Prospectivos , Condicionamento Pré-Transplante
10.
Biochimie ; 176: 103-109, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32621943

RESUMO

Thermostability is a fundamental characteristic of enzymes that is of high importance for industrial implementation of enzymatic catalysis. Cellobiohydrolases are enzymes capable to hydrolyze the most abundant natural polysaccharide - cellulose. These enzymes are widely applied in industry for processing of cellulose containing materials. However, structural and functional engineering of cellobiohydrolases for improving their properties is a challenging task. In this study, the thermostability of Penicillium verruculosum Cel7A cellobiohydrolase was increased through rational design of substitutions with proline. The stabilizing substitution G415P resulted in 3.4-fold increase in half-life time at 60 °C compared to wild-type enzyme. Molecular dynamics simulations indicated a clear effect of the stabilizing substitution G415P and the destabilizing substitutions D62P, S191P, and S273P on the stability of the enzyme tertiary structure. The stabilizing substitution G415P decreased flexibility of the lateral sides of the enzyme active site tunnel, while the considered destabilizing substitutions increased their flexibility.


Assuntos
Substituição de Aminoácidos , Celulose 1,4-beta-Celobiosidase , Proteínas Fúngicas , Simulação de Dinâmica Molecular , Mutação de Sentido Incorreto , Talaromyces , Celulose 1,4-beta-Celobiosidase/química , Celulose 1,4-beta-Celobiosidase/genética , Estabilidade Enzimática/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Domínios Proteicos , Talaromyces/enzimologia , Talaromyces/genética
11.
Bioresour Technol ; 296: 122370, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31734058

RESUMO

Thermostability and stability in ionic liquids are essential properties of cellulases that are applied in industrial processes of bioconversion. Engineering of protein surface of endoglucanase II from Penicillium verruculosum was used to improve the enzyme thermostability and stability in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). The engineering was based on analysis of the protein surface topography and enhanced by multiple sequence alignment and ΔΔG calculations. In the case of the thermostability, half-life time was improved in 1.3-1.6 times at 70 °C and 1.2-1.4 times at 80 °C. In the case of the stability in [Bmim]Cl, the residual activity after 72 h of incubation in the presence of [Bmim]Cl (50 g/L, 50 °C, pH 4.5) was 1.7-1.9 times greater for the tailored enzyme. The yield of reducing sugars after enzymatic hydrolysis of aspen wood pretreated with [Bmim]Cl was 10-20% higher with the tailored endoglucanase.


Assuntos
Celulase , Líquidos Iônicos , Penicillium , Engenharia , Imidazóis
12.
ACS Appl Mater Interfaces ; 10(41): 34849-34868, 2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30230807

RESUMO

The incorporation of bioactive compounds onto polymer fibrous scaffolds with further control of drug release kinetics is essential to improve the functionality of scaffolds for personalized drug therapy and regenerative medicine. In this study, polymer and hybrid microcapsules were prepared and used as drug carriers, which are further deposited onto polymer microfiber scaffolds [polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB), and PHB doping with the conductive polyaniline (PANi) of 2 wt % (PHB-PANi)]. The number of immobilized microcapsules decreased with increase in their ζ-potential due to electrostatic repulsion with the negatively charged fiber surface, depending on the polymer used for the scaffold's fabrication. Additionally, the immobilization of the capsules in dynamic mechanical conditions at a frequency of 10 Hz resulted in an increase in the number of the capsules on the fibers with increase in the scaffold piezoelectric response in the order PCL < PHB < PHB-PANi, depending on the chemical composition of the capsules. The immobilization of microcapsules loaded with different bioactive molecules onto the scaffold surface enabled multimodal triggering by physical (ultrasound, laser radiation) and biological (enzymatic treatment) stimuli, providing controllable release of the cargo from scaffolds. Importantly, the microcapsules immobilized onto the surface of the scaffolds did not influence the cell growth, viability, and cell proliferation on the scaffolds. Moreover, the attachment of human mesenchymal stem cells (hMSCs) on the scaffolds revealed that the PHB and PHB-PANi scaffolds promoted adhesion of hMSCs compared to that of the PCL scaffolds. Two bioactive compounds, antibiotic ceftriaxone sodium (CS) and osteogenic factor dexamethasone (DEXA), were chosen to load the microcapsules and demonstrate the antimicrobial properties and osteogenesis of the scaffolds. The modified scaffolds had prolonged release of CS or DEXA, which provided an improved antimicrobial effect, as well as enhanced osteogenic differentiation and mineralization of the scaffolds modified with capsules compared to that of individual scaffolds soaked in CS solution or incubated in an osteogenic medium. Thus, the immobilization of microcapsules provides a simple, convenient way to incorporate bioactive compounds onto polymer scaffolds, which makes these multimodal materials suitable for personalized drug therapy and bone tissue engineering.


Assuntos
Antibacterianos , Ceftriaxona , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Osteogênese/efeitos dos fármacos , Alicerces Teciduais/química , Antibacterianos/química , Antibacterianos/farmacologia , Cápsulas , Ceftriaxona/química , Ceftriaxona/farmacologia , Humanos , Células-Tronco Mesenquimais/citologia , Poliésteres/química , Poliésteres/farmacologia , Proibitinas
13.
3 Biotech ; 8(9): 396, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30221109

RESUMO

Mutant forms of recombinant endoglucanase II (EG II, N194A), cellobiohydrolase I (CBH I, N45A) and cellobiohydrolase II (CBH II, N219A) from Penicillium verruculosum with enhanced cellulase activities, achieved by engineering of enzyme N-glycosylation sites in our previous studies, were used as components of the binary and ternary mixtures of cellulases in hydrolysis of Avicel and milled aspen wood. Using the engineered forms of the enzymes at a dosage of 10 mg/g substrate resulted in significant boosting of the glucose release from cellulose in the presence of excess ß-glucosidase relative to the performance of the corresponding wild-type mixtures at the same loading. The boosting effects reached 11-40% depending on the reaction time and substrate type. In hydrolysis of both cellulosic substrates by the binary mixtures of cellulases, all the enzyme pairs exhibited synergism. The magnitude of the synergistic effects (Ks) did not depend notably upon the induced mutations in the enzymes, and they were in the range of 1.3-1.8 for the combinations of EG II with CBH I (or CBH II), and 2.3-2.9 for the CBH I-CBH II pair. The results of this study should provide a basis for the development of a more effective fungal strain capable of producing cellulase cocktails with enhanced hydrolytic performance against lignocellulosic materials.

14.
Bioresour Technol ; 250: 429-438, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29195155

RESUMO

The pretreatment of softwood and hardwood samples (spruce and hornbeam wood) with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was undertaken for further simultaneous enzymatic saccharification of renewable non-food lignocellulosic biomass and microbial fermentation of obtained sugars to ethanol and fumaric acid. A multienzyme cocktail based on cellulases and yeast or fungus cells producing ethanol and fumaric acid were the main objects of [Bmim]Cl influence studies. A complex effect of lignocellulosic biomass pretreatment with [Bmim]Cl on various aspects of the process (both action of cellulases and microbial conversion of hydrolysates to target products) was revealed. Positive effects of the pretreatment with [Bmim]Cl included decreasing the lignin content in the biomass, and increasing the effectiveness of enzymatic hydrolysis and microbial transformation of pretreated biomass. Immobilized cells of both yeasts and fungi possessed improved productive characteristics in the biotransformation of biomass pretreated with [Bmim]Cl to ethanol and fumaric acid.


Assuntos
Etanol , Imidazóis , Biomassa , Células Imobilizadas , Fermentação , Fumaratos , Hidrólise , Líquidos Iônicos , Lignina
15.
Biochimie ; 132: 102-108, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27856189

RESUMO

Cellobiohydrolases (CBHs), belonging to glycoside hydrolase families 6 and 7 (GH6 and GH7), are the major components of cellulase systems of filamentous fungi involved in biodegradation of cellulose in nature. Previous studies demonstrated that N-linked glycans in the catalytic domains of GH7 CBHs significantly affect the enzyme activity against cellulosic substrates. The influence of N-linked glycans on the activity and processivity of recombinant GH6 CBH II from Penicillium verruculosum (PvCel6A) was studied using site-directed mutagenesis of the respective Asn residues. Depending on the position of N-glycans on the surface of a protein globule, they affected the enzyme activity against cellulose either negatively or positively. The decrease or increase in the degree of processivity of recombinant forms of PvCel6A generally correlated with activity changes against Avicel. The mechanism of the N-glycan influence seems to be universal for GH6 and GH7 CBHs. The observed effects for CBHs from both families are explained in terms of a mechanistic model that also makes clear our previously published data on the highly active CBH IIb from Myceliophthora thermophila (MtCel6B). This study, together with data of other researchers, strongly suggests that the N-linked glycans in the catalytic domains of GH6 and GH7 CBHs are involved in processive catalytic machinery of these enzymes. Data obtained should be taken into account during development of new and more effective biocatalysts by protein engineering techniques.


Assuntos
Celulose 1,4-beta-Celobiosidase/metabolismo , Proteínas Fúngicas/metabolismo , Penicillium/enzimologia , Polissacarídeos/metabolismo , Sequência de Aminoácidos , Biocatálise , Domínio Catalítico , Celulose/metabolismo , Celulose 1,4-beta-Celobiosidase/química , Celulose 1,4-beta-Celobiosidase/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glicosilação , Modelos Moleculares , Mutação , Penicillium/genética , Penicillium/metabolismo , Domínios Proteicos , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos
16.
Protein Eng Des Sel ; 29(11): 495-502, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27440076

RESUMO

Endoglucanase IIa from Penicillium verruculosum (PvCel5A) has three potential N-glycosylation sites: Asn19, Asn42 and Asn194. In order to study the role of N-glycosylation, the wild type (wt) PvCel5A and its mutant forms, carrying Asn to Ala substitutions, were cloned into Penicillium canescens. All forms of the rPvCel5A were successfully expressed and purified for characterization. The MALDI-TOF mass spectrometry peptide fingerprinting showed that N-glycans linked to Asn42 and Asn194 represent variable oligosaccharides, according to the formula (Man)1-9(GlcNAc)2. No evidence for Asn19 glycosylation was found. Mutations had no notable effect on the enzyme thermostability; however, the N-linked glycans stabilized the enzyme against proteolytic attack. For N42A and N194A mutants, a slight shift of pH-optimum to pH 5.0 was observed (from pH-optimum of 4.5 for the native enzyme, rPvCel5A-wt and N19A mutant). The N19A mutation led to a notable decrease in the specific activity against carboxymethylcellulose and barley ß-glucan (by 26% and 12% relative to the rPvCel5A-wt), while the N42A and N194A mutants displayed 12-13% and 32-35% increase in the activities. Similar effects of the mutations were observed in prolonged hydrolysis of ß-glucan and milled aspen wood by rPvCel5A forms in the presence of purified ß-glucosidase.

17.
Biotechnol Bioeng ; 113(2): 283-91, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26301455

RESUMO

Cellobiohydrolase I from Penicillium verruculosum (PvCel7A) has four potential N-glycosylation sites at its catalytic module: Asn45, Asn194, Asn388, and Asn430. In order to investigate how the N-glycosylation influences the activity and other properties of the enzyme, the wild type (wt) PvCel7A and its mutant forms, carrying Asn to Ala substitutions, were cloned into Penicillium canescens PCA10 (niaD-) strain, a fungal host for production of heterologous proteins. The rPvCel7A-wt and N45A, N194A, N388A mutants were successfully expressed and purified for characterization, whereas the expression of N430A mutant was not achieved. The MALDI-TOF mass spectrometry fingerprinting of peptides, obtained as a result of digestion of rPvCel7A forms with specific proteases, showed that the N-linked glycans represent variable high-mannose oligosaccharides and the products of their sequential enzymatic trimming, according to the formula (Man)0-13 (GlcNAc)2 , or a single GlcNAc residue. Mutations had no notable effect on pH-optimum of PvCel7A activity and enzyme thermostability. However, the mutations influenced both the enzyme adsorption ability on Avicel and its activity against natural and synthetic substrates. In particular, the N45A mutation led to a significant increase in the rate of Avicel and milled aspen wood hydrolysis, while the substrate digestion rates in the case of N194A and N388A mutants were notably lower relative to rPvCel7A-wt. These data, together with data of 3D structural modeling of the PvCel7A catalytic module, indicate that the N-linked glycans are an important part of the processive catalytic machinery of PvCel7A.


Assuntos
Celulose 1,4-beta-Celobiosidase/química , Celulose 1,4-beta-Celobiosidase/metabolismo , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Penicillium/metabolismo , Polissacarídeos/análise , Substituição de Aminoácidos , Celulose/metabolismo , Celulose 1,4-beta-Celobiosidase/genética , Celulose 1,4-beta-Celobiosidase/isolamento & purificação , Estabilidade Enzimática , Glicosilação , Concentração de Íons de Hidrogênio , Hidrólise , Proteínas Mutantes/genética , Proteínas Mutantes/isolamento & purificação , Penicillium/genética , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Temperatura
18.
Alcohol Clin Exp Res ; 39(7): 1128-36, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26058418

RESUMO

BACKGROUND: The medications produced from natural products are widely used as prophylactics for sickness induced by alcohol consumption. One such prophylactic is produced from the Reishi mushroom, Ganoderma lucidum. Because of the antioxidant properties of these preparations, we expect neuroprotective prophylactic effects of Reishi-based medications in alcohol-treated animals. METHODS: The Reishi (R) suspension was produced as water extract from Altaian mushrooms. Sprague-Dawley male rats were separated into the following 3 experimental groups: Group A + R received R (6 days per week) starting 1 week before alcohol exposure, and during the next 3 weeks, they received both R and alcohol; group A received alcohol; and group C received water. At the end of experiment, we determined the metabolic profile using proton magnetic resonance spectroscopy ((1) H MRS) of the brain cortex and phosphorus magnetic resonance spectroscopy of the liver. Additionally, the blood cells were collected, and the serum biochemistry and liver histology were performed after euthanasia. RESULTS: Partial least squares discriminant analysis processing of the brain (1) H MRS gave 2 axes, the Y1 axis positively correlated with the level of taurine and negatively correlated with the level of lactate, and the Y2 axis positively correlated with the content of GABA and glycine and negatively correlated with the sum of the excitatory neurotransmitters, glutamate and glutamine. The Y1 values reflecting the brain energetics for the A + R group exceeded the corresponding values for groups C and A. The maximal level of Y2 reflecting the prevalence of inhibitory metabolites in the brain was observed in the rats exposed to alcohol. Moderate alcohol consumption did not cause significant pathological changes in the livers of the experimental animals. However, 20 days of alcohol consumption significantly increased the number of binuclear hepatocytes compared to the control. This effect was mitigated in the rats that received the Reishi extract. CONCLUSIONS: Regular administration of the Reishi suspension improved the energy supply to the brain cortex and decreased the prevalence of inhibitory neurotransmitters that are characteristic of alcohol consumption. The alcohol-induced increase in liver proliferation was significantly suppressed by regular administration of the G. lucidum water suspension.


Assuntos
Transtornos Relacionados ao Uso de Álcool/prevenção & controle , Produtos Biológicos/uso terapêutico , Reishi , Consumo de Bebidas Alcoólicas/sangue , Animais , Produtos Biológicos/farmacologia , Peso Corporal/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Hepatócitos/efeitos dos fármacos , Masculino , Espectroscopia de Prótons por Ressonância Magnética , Ratos Sprague-Dawley
19.
Brain Behav Immun ; 26(3): 451-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22178900

RESUMO

Modulation of social signals by antigen-induced immunoenhancement is a significant component of behavioral and reproductive adaptations of a host population to parasitic pressure. To investigate this concept, we studied odor attractiveness and reproductive output of ICR male mice treated with keyhole limpet hemocyanin (KLH) as an antigenic stimulus. We collected urine samples for olfactory preference tests (control vs. KLH administration) on different days following treatment. We found that the differences in odor attractiveness between control and immunized males, which were observed on the 3rd day, disappeared soon afterwards. Odor attractiveness of male mice positively correlated with their immunoresponsiveness, which was assessed by the sum of anti-KLH IgG1 and anti-KLH IgG2a titers. According to the hypothesis of terminal investment, antigen-treated males had higher reproductive output in comparison with control males and produced more progeny as a result.


Assuntos
Antígenos/imunologia , Reprodução/imunologia , Comportamento Sexual Animal/fisiologia , Olfato/imunologia , Animais , Hemocianinas , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Masculino , Camundongos , Odorantes , Vacinação/veterinária
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