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Intrinsic self-healing polymers via dynamic covalent bonds have been attracting extensive attention because of their repeatable self-healing property. Herein, a novel self-healing epoxy resin was synthesized with disulfide-containing curing agent via the condensation of dimethyl 3,3'-dithiodipropionate (DTPA) and polyether amine (PEA). Therefore, in the structure of cured resin, flexible molecular chains and disulfide bonds were imported into the cross-linked polymer networks for triggering self-healing performance. The self-healing reaction of cracked samples was realized under a mild condition (60 °C for 6 h). The distribution of flexible polymer segments, disulfide bonds and hydrogen bonds in cross-linked networks plays a great role in the self-healing process of prepared resins. The molar ratio of PEA and DTPA strongly affects the mechanical performance and self-healing property. Especially when that molar ratio of PEA to DTPA is 2, the cured self-healing resin sample showed great ultimate elongation (795%) and excellent healing efficiency (98%). The products can be used as an organic coating, in which the crack could self-repair during a limited time. The corrosion resistance of a typical cure coating sample has been testified by an immersion experiment and electrochemistry impedance spectrum (EIS). This work provided a simple and low-cost route to prepare a self-healing coating for prolonging the service life of conventional epoxy coatings.
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Reactive oxygen species (ROS) play important regulatory roles in plant growth and development, as well as in cell differentiation and stress responses. Respiratory burst oxidase homolog (RBOH) is the key enzyme in ROS production. So far, the Rboh family genes in Pyropia yezoensis have not been comprehensively characterized, and whether their function was involved in the formation of archeospores is still unknown. In this study, a total of 11 PyRboh genes were identified from the P. yezoensis genome by homology mining. Through phylogenetic analysis, it is suggested that the PyRboh genes were evolutionarily conserved among the lineages of red algae, but a few genes exhibited a species-specific manner. The treatment of P. yezoensis blades with NADPH oxidase inhibitor diphenylene iodonium (DPI) could significantly inhibit the formation of archeospores, suggesting that RBOH may be involved in the formation of archeospores. According to PyRboh gene expression analysis using the P. yezoensis strains with obvious differences in releasing archeospores, it is showed that the expression trends of most genes were consistent, with no significant difference between strains, whereas the expression pattern of the two P. yezoensis-specific genes (PyRbohJ and PyRbohK) was positively correlated with the amount of archeospores. Furthermore, as treatment of blades with allantoin resulted in a significant increase in the release of archeospores, the expression levels of PyRbohJ and PyRbohK were also consistently upregulated, further confirming the relationship between the two genes and archeospore formation. These findings provide insights into the molecular mechanism of P. yezoensis archeospore formation.
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Splicing of plant organellar group II introns is under accurate nuclear control that employs many nucleus-encoded protein cofactors from various families. For mitochondrial introns, only a few splicing factors have been characterized because disruption of their functions often causes embryo lethality. Here, we report the function of Empty Pericarp8 (Emp8) in the splicing of three group II introns in mitochondria, complex I biogenesis, and seed development in maize. Emp8 encodes a P subfamily pentatricopeptide repeat protein that localizes in mitochondria. The loss-of-function mutants of Emp8 are embryo lethal, showing severely arrested embryo and endosperm development in maize. The respiration rate in the emp8 mutants is reduced with substantially enhanced expression of alternative oxidases. Transcript analysis indicated that the trans-splicing of nad1 intron 4 and cis-splicing of nad4 intron 1 are abolished, and the cis-splicing of nad2 intron 1 is severely impaired in the emp8 mutants. These defects consequently lead to the disassembly of mitochondrial complex I and a dramatic reduction in its activity. Together, these results suggest that Emp8 is required for the trans-splicing of nad1 intron 4 and cis-splicing of nad4 intron 1 and nad2 intron 1, which is essential to mitochondrial complex I assembly and hence to embryogenesis and endosperm development in maize.
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Dictyopteris divaricata is a kind of important brown algae with many biological activities. It has been receiving more and more attention, yet there are rarely studies done on its polysaccharides. In this study, the optimum extraction and biological activity of seaweed polysaccharides from Dictyopteris divaricata (DDSP) were investigated. Response surface methodology (RSM), based on a three-level, three-variable Box-Behnken design (BBD), was employed to obtain the best possible combinations for maximum polysaccharides yield. The optimum extraction conditions were as follows: liquid-solid ratio of 110â¯mL/g, extraction time of 6â¯h and extraction temperature of 100⯰C. Under these conditions, the experimental yield was 3.05%, which was in close agreement with the predicted value of 3.15%. The average molecular weight of DDSP was 58.05â¯kDa. Gas chromatograph (GC) results showed that DDSP was composed of fucose, xylose, mannose, glucose and galactose with the corresponding molar ratio of 4.45:2.74:1.00:2.94:1.35. Biological activity showed that DDSP exhibited strong antioxidant activity in vitro and possessed the potential on stimulating immune response of RAW264.7 cells. So DDSP can be used as a natural ingredient in functional foods.
Assuntos
Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Phaeophyceae/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Alga Marinha/química , Sulfatos/química , Animais , Compostos de Bifenilo/química , Radical Hidroxila/química , Fatores Imunológicos/isolamento & purificação , Camundongos , Monossacarídeos/análise , Picratos/química , Polissacarídeos/isolamento & purificação , Células RAW 264.7RESUMO
Animals living at high altitudes have evolved distinct phenotypic and genotypic adaptations against stressful environments. We studied the adaptive patterns of altitudinal stresses on transcriptome turnover in subterranean plateau zokors (Myospalax baileyi) in the high-altitude Qinghai-Tibetan Plateau. Transcriptomes of zokors from three populations with distinct altitudes and ecologies (Low: 2846 m, Middle: 3282 m, High: 3,714 m) were sequenced and compared. Phylogenetic and principal component analyses classified them into three divergent altitudinal population clusters. Genetic polymorphisms showed that the population at H, approaching the uppermost species boundary, harbors the highest genetic polymorphism. Moreover, 1056 highly up-regulated UniGenes were identified from M to H. Gene ontologies reveal genes like EPAS1 and COX1 were overexpressed under hypoxia conditions. EPAS1, EGLN1, and COX1 were convergent in high-altitude adaptation against stresses in other species. The fixation indices (F ST and G ST )-based outlier analysis identified 191 and 211 genes, highly differentiated among L, M, and H. We observed adaptive transcriptome changes in Myospalax baileyi, across a few hundred meters, near the uppermost species boundary, regardless of their relatively stable underground burrows' microclimate. The highly variant genes identified in Myospalax were involved in hypoxia tolerance, hypercapnia tolerance, ATP-pathway energetics, and temperature changes.
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Adaptação Fisiológica , Perfilação da Expressão Gênica/métodos , Muridae/classificação , Polimorfismo Genético , Altitude , Animais , Hipóxia Celular , Evolução Molecular , Regulação da Expressão Gênica , Muridae/genética , Muridae/fisiologia , Filogenia , Análise de Componente Principal , Análise de Sequência de RNA , TibetRESUMO
The whole chloroplast genome (cp DNA) sequence of Caulerpa lentillifera J. Agardh has been characterized from Illumina pair-end sequencing. The circular cpDNA was 119,402 bp in length, containing 122 genes, which included 91 protein-coding genes, 28 tRNA genes, and 3 ribosomal RNA genes (four rRNA species). The overall AT content of C. lentillifera cpDNA is 67.4%. The 48 genes phylogenetic analysis suggested that C. lentillifera formed a monophyletic clade with congeneric C. racemosa.
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Caulerpa cupressoides (Vahl) C. Agardh is a widely distributed tropical green algae. The circular chloroplast genome was 130,895 bp in length, with a GC content of 34%. In total, 99 genes were identified and they were consisted of 63 coding genes, 30 tRNA genes, and 6 rRNA genes. This chloroplast genome did not show an obvious quadripartite structure. Phylogenetic analysis revealed that C. cupressoides, C. racemosa, and Tydemania expeditionis were close relatives, with high bootstrap values. The characterized complete chloroplast genome of C. cupressoides will provide essential date for further studies of Bryopsidales.
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This report describes the draft genome sequences of two strains, Pseudoalteromonas telluritireducens DSM 16098 and P. spiralis DSM 16099, which were isolated from hydrothermal vents of the Juan de Fuca Ridge. The reads generated by an Ion Torrent PGM were assembled into contigs with total sizes of 4.4 Mb and 4.1 Mb for DSM 16098 and DSM 16099, respectively.
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This report describes the draft genome sequence of Alcanivorax sp. strain KX64203, isolated from deep-sea sediment samples. The reads generated by an Ion Torrent PGM were assembled into contigs, with a total size of 4.76 Mb. The data will improve our understanding of the strain's function in alkane degradation.
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The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met(5)]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met(5)]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors.
Assuntos
Crassostrea/genética , Fatores de Transcrição de Choque Térmico/genética , NF-kappa B/genética , Neurotransmissores/genética , Fator de Necrose Tumoral alfa/farmacologia , Animais , Apoptose , Crassostrea/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/efeitos dos fármacos , Hemócitos/efeitos dos fármacos , Hemócitos/fisiologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Fagocitose , Dobramento de Proteína/efeitos dos fármacos , Análise de Sequência de RNA/métodosRESUMO
Yesso scallop-pathogenic Vibrio splendidus strain JZ6 was found to have the highest virulence at 10°C, while its pathogenicity was significantly reduced with increased temperature and completely incapacitated at 28°C. In the present study, comparative transcriptome analyses of JZ6 and another nonpathogenic V. splendidus strain, TZ19, were conducted at two crucial culture temperatures (10°C and 28°C) in order to determine the possible mechanism of temperature regulation of virulence. Comparisons among four libraries, constructed from JZ6 and TZ19 cultured at 10°C and 28°C (designated JZ6_10, JZ6_28, TZ19_10, and TZ19_28), revealed that 241 genes were possibly related to the increased virulence of JZ6 at 10°C. There were 10 genes, including 2 encoding Flp pilus assembly proteins (FlhG and VS_2437), 6 encoding proteins of the "Vibrio cholerae pathogenic cycle" (ToxS, CqsA, CqsS, RpoS, HapR, and Vsm), and 2 encoding proteins in the Sec-dependent pathway (SecE and FtsY), that were significantly upregulated in JZ6_10 (P < 0.05) compared to those in JZ6_28, TZ19_10, and TZ19_28, which were supposed to be responsible for adhesion, quorum sensing, virulence, and protein secretion of V. splendidus. When cultured at 10°C, JZ6 cells were larger and tended to aggregate more than those cultured at 28°C. The virulence factor (extracellular metalloprotease) was also found to be highly expressed in the extracellular product (ECP) of JZ6 at 10°C, and this ECP exhibited obvious cytotoxicity to oyster primary hemocytes, A549 cells, and L929 cells. These results indicated that low temperatures (10°C) could enhance adhesion, activate the quorum sensing systems, upregulate virulence factor synthesis and secretion, and, lastly, increase the pathogenicity of JZ6.
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Proteínas de Bactérias/genética , Ostreidae/microbiologia , Transcriptoma , Vibrio/genética , Vibrio/patogenicidade , Animais , Proteínas de Bactérias/metabolismo , Temperatura Baixa , Perfilação da Expressão Gênica , Frutos do Mar/microbiologia , Vibrio/metabolismo , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
BACKGROUND: Neural-endocrine-immune (NEI) system is a major modulation network among the nervous, endocrine and immune system and weights greatly in maintaining homeostasis of organisms during stress and infection. Some microRNAs are found interacting with NEI system (designated NeurimmiRs), addressing swift modulations on immune system. The oyster Crassostrea gigas, as an intertidal bivalve, has evolved a primary NEI system. However, the knowledge about NeurimmiRs in oysters remains largely unknown. RESULTS: Six small RNA libraries from haemocytes of oysters stimulated with acetylcholine (ACh) and norepinephrine (NE) were sequenced to identify neurotransmitter-responsive miRNAs and survey their immunomodulation roles. A total of 331 miRNAs (132 identified in the present study plus 199 identified previously) were subjected to expression analysis, and twenty-one and sixteen of them were found ACh- or NE-responsive, respectively (FDR < 0.05). Meanwhile, 21 miRNAs exhibited different expression pattern after ACh or NE stimulation. Consequently, 355 genes were predicted as putative targets of these neurotransmitter-responsive miRNAs in oyster. Through gene onthology analysis, multiple genes involved in death, immune system process and response to stimulus were annotated to be modulated by NeurimmiRs. Besides, a significant decrease in haemocyte phagocytosis and late-apoptosis or necrosis rate was observed after ACh and NE stimulation (p < 0.05) while early-apoptosis rate remained unchanged. CONCLUSIONS: A comprehensive immune-related network involving PRRs, intracellular receptors, signaling transducers and immune effectors was proposed to be modulated by ACh- and NE-responsive NeurimmiRs, which would be indispensable for oyster haemocytes to respond against stress and infection. Characterization of the NeurimmiRs would be an essential step to understand the NEI system of invertebrate and the adaptation mechanism of oyster.
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Crassostrea/imunologia , Hemócitos/imunologia , MicroRNAs/imunologia , Acetilcolina/imunologia , Animais , Apoptose , Crassostrea/citologia , Imunomodulação , Norepinefrina/imunologia , Fagocitose , Receptores de Superfície Celular/imunologiaRESUMO
Gene duplication has been proposed to serve as the engine of evolutionary innovation. It is well recognized that eukaryotic genomes contain a large number of duplicated genes that evolve new functions or expression patterns. However, in mollusks, the evolutionary mechanisms underlying the divergence and the functional maintenance of duplicate genes remain little understood. In the present study, we performed a comprehensive analysis of duplicate genes in the protein kinase superfamily using whole genome and transcriptome data for the Pacific oyster. A total of 64 duplicated gene pairs were identified based on a phylogenetic approach and the reciprocal best BLAST method. By analyzing gene expression from RNA-seq data from 69 different developmental and stimuli-induced conditions (nine tissues, 38 developmental stages, eight dry treatments, seven heat treatments, and seven salty treatments), we found that expression patterns were significantly correlated for a number of duplicate gene pairs, suggesting the conservation of regulatory mechanisms following divergence. Our analysis also identified a subset of duplicate gene pairs with very high expression divergence, indicating that these gene pairs may have been subjected to transcriptional subfunctionalization or neofunctionalization after the initial duplication events. Further analysis revealed a significant correlation between expression and sequence divergence (as revealed by synonymous or nonsynonymous substitution rates) under certain conditions. Taken together, these results provide evidence for duplicate gene sequence and expression divergence in the Pacific oyster, accompanying its adaptation to harsh environments. Our results provide new insights into the evolution of duplicate genes and their expression levels in the Pacific oyster.
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RNA editing, converting cytidines (C) to uridines (U) at specific sites in the transcripts of mitochondria and plastids, plays a critical role in organelle gene expression in land plants. Recently pentatricopeptide repeat (PPR) proteins were identified as site-specific recognition factors for RNA editing. In this study, we characterized an empty pericarp7 mutant (emp7) in Zea mays (maize), which confers an embryo-lethal phenotype. In emp7 mutants, mitochondrial functions are seriously perturbed, resulting in a strikingly reduced respiration rate. Emp7 encodes an E-subgroup PPR protein that is localized exclusively in the mitochondrion. Null mutation of Emp7 abolishes the C â U editing of ccmF(N) transcript solely at position 1553. CcmF(N) is coding for a subunit of heme lyase complex in the cytochrome c maturation pathway. The resulting Phe â Ser substitution in CcmF(N) leads to the loss of CcmF(N) protein and a strikingly reduced c-type cytochrome. Consequently, the mitochondrial cytochrome-linked respiratory chain is impaired as a result of the disassembly of complex III in the emp7 mutant. These results indicate that the PPR-E subgroup protein EMP7 is required for C â U editing of ccmF(N) -1553 at a position essential for cytochrome c maturation and mitochondrial oxidative phosphorylation, and hence is essential to embryo and endosperm development in maize.
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Mitocôndrias/metabolismo , Proteínas de Plantas/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Citocromos c/genética , Regulação da Expressão Gênica de Plantas , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Proteínas de Plantas/genética , Sementes/genética , Zea mays/genéticaRESUMO
Tumor necrosis factor superfamily (TNFSF) members represent a group of cytokines participating in diverse immunological, pathological and developmental pathways. However, compared with deuterostomia and cnidaia, the composition and evolution of TNF homologous in protostomia are still not well understood. In the present study, a total of 81 TNF superfamily (TNFSF) genes from 15 mollusk species, including 23 TNFSF genes from Crassostrea gigas, were surveyed by genome-wide bioinformatics analysis. The phylogenetic analysis showed that 14 out of 23 C. gigas TNFSF genes in five clades exhibited orthologous relationships with Pinctada fucata TNFSF genes. Moreover, there were 15 C. gigas TNFSF genes located in oyster-specific clusters, which were contributed by small-scaled tandem and/or segmental duplication events in oyster. By comparing the sequences of duplicated TNFSF pairs, exon loss and variant in exon/intron length were revealed as the major modes of divergence in gene structure. Most of the duplicated C. gigas TNFSF pairs were evolved under purifying selection with consistent tissue expression patterns, implying functional constraint shaped diversification. This study demonstrated the expansion and early divergence of TNF superfamily in C. gigas, which provides potential insight into revealing the evolution and function of this superfamily in mollusk.
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Crassostrea/imunologia , Éxons/genética , Íntrons/genética , Fatores de Necrose Tumoral/metabolismo , Animais , Evolução Biológica , Biologia Computacional/métodos , Duplicação Gênica , Regulação da Expressão Gênica , Genoma , Filogenia , Polimorfismo Genético , Seleção Genética , Especificidade da Espécie , Fatores de Necrose Tumoral/genéticaRESUMO
BACKGROUND: Non-productive binding of enzymes to lignin is thought to impede the saccharification efficiency of pretreated lignocellulosic biomass to fermentable sugars. Due to a lack of suitable analytical techniques that track binding of individual enzymes within complex protein mixtures and the difficulty in distinguishing the contribution of productive (binding to specific glycans) versus non-productive (binding to lignin) binding of cellulases to lignocellulose, there is currently a poor understanding of individual enzyme adsorption to lignin during the time course of pretreated biomass saccharification. RESULTS: In this study, we have utilized an FPLC (fast protein liquid chromatography)-based methodology to quantify free Trichoderma reesei cellulases (namely CBH I, CBH II, and EG I) concentration within a complex hydrolyzate mixture during the varying time course of biomass saccharification. Three pretreated corn stover (CS) samples were included in this study: Ammonia Fiber Expansion(a) (AFEX™-CS), dilute acid (DA-CS), and ionic liquid (IL-CS) pretreatments. The relative fraction of bound individual cellulases varied depending not only on the pretreated biomass type (and lignin abundance) but also on the type of cellulase. Acid pretreated biomass had the highest levels of non-recoverable cellulases, while ionic liquid pretreated biomass had the highest overall cellulase recovery. CBH II has the lowest thermal stability among the three T. reesei cellulases tested. By preparing recombinant family 1 carbohydrate binding module (CBM) fusion proteins, we have shown that family 1 CBMs are highly implicated in the non-productive binding of full-length T. reesei cellulases to lignin. CONCLUSIONS: Our findings aid in further understanding the complex mechanisms of non-productive binding of cellulases to pretreated lignocellulosic biomass. Developing optimized pretreatment processes with reduced or modified lignin content to minimize non-productive enzyme binding or engineering pretreatment-specific, low-lignin binding cellulases will improve enzyme specific activity, facilitate enzyme recycling, and thereby permit production of cheaper biofuels.
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Micro ribonucleic acids (miRNAs) represent a class of small noncoding RNAs that play important roles in multiple biological processes by degrading targeted mRNAs or by repressing mRNA translation. In the case of algal lineages, especially dinoflagellates, knowledge regarding the miRNA system is still limited and its regulatory role remains unclear. In the present study, a computational approach was employed to screen miRNAs from the expressed sequence tags (ESTs) of Alexandrium tamarense. A total of 18 potential miRNAs were identified according to a range of filtering criteria. In addition, unique evolutionary features, such as miRNA gene duplication and sequence similarity to metazoan miRNAs, implied that the miRNA system in dinoflagellates is complex. Moreover, based on these 18 miRNA sequences, 42 potential target genes showing diverse functions in regulating growth and development were predicted in Thalassiosira pseudonana and Phaeodactylum tricornutum. Taken together, our data suggest the existence of miRNAs in dinoflagellates and provide clues for further functional studies on these predicted miRNAs.
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Substrate binding is typically one of the rate-limiting steps preceding enzyme catalytic action during homogeneous reactions. However, interfacial-based enzyme catalysis on insoluble crystalline substrates, like cellulose, has additional bottlenecks of individual biopolymer chain decrystallization from the substrate interface followed by its processive depolymerization to soluble sugars. This additional decrystallization step has ramifications on the role of enzyme-substrate binding and its relationship to overall catalytic efficiency. We found that altering the crystalline structure of cellulose from its native allomorph I(ß) to III(I) results in 40-50% lower binding partition coefficient for fungal cellulases, but surprisingly, it enhanced hydrolytic activity on the latter allomorph. We developed a comprehensive kinetic model for processive cellulases acting on insoluble substrates to explain this anomalous finding. Our model predicts that a reduction in the effective binding affinity to the substrate coupled with an increase in the decrystallization procession rate of individual cellulose chains from the substrate surface into the enzyme active site can reproduce our anomalous experimental findings.
Assuntos
Celulose/metabolismo , Biocombustíveis , Celulase/metabolismo , Celulose/química , Proteínas Fúngicas/metabolismo , Hidrólise , Cinética , Lignina/química , Lignina/metabolismo , Ligação Proteica , Especificidade por Substrato , Trichoderma/enzimologiaRESUMO
Conversion of lignocellulose to biofuels is partly inefficient due to the deleterious impact of cellulose crystallinity on enzymatic saccharification. We demonstrate how the synergistic activity of cellulases was enhanced by altering the hydrogen bond network within crystalline cellulose fibrils. We provide a molecular-scale explanation of these phenomena through molecular dynamics (MD) simulations and enzymatic assays. Ammonia transformed the naturally occurring crystalline allomorph I(ß) to III(I), which led to a decrease in the number of cellulose intrasheet hydrogen bonds and an increase in the number of intersheet hydrogen bonds. This rearrangement of the hydrogen bond network within cellulose III(I), which increased the number of solvent-exposed glucan chain hydrogen bonds with water by ~50%, was accompanied by enhanced saccharification rates by up to 5-fold (closest to amorphous cellulose) and 60-70% lower maximum surface-bound cellulase capacity. The enhancement in apparent cellulase activity was attributed to the "amorphous-like" nature of the cellulose III(I) fibril surface that facilitated easier glucan chain extraction. Unrestricted substrate accessibility to active-site clefts of certain endocellulase families further accelerated deconstruction of cellulose III(I). Structural and dynamical features of cellulose III(I), revealed by MD simulations, gave additional insights into the role of cellulose crystal structure on fibril surface hydration that influences interfacial enzyme binding. Subtle alterations within the cellulose hydrogen bond network provide an attractive way to enhance its deconstruction and offer unique insight into the nature of cellulose recalcitrance. This approach can lead to unconventional pathways for development of novel pretreatments and engineered cellulases for cost-effective biofuels production.
Assuntos
Actinomycetales/enzimologia , Celulase/metabolismo , Celulose/química , Celulose/metabolismo , Trichoderma/enzimologia , Actinomycetales/química , Celulase/química , Cristalografia por Raios X , Gossypium/química , Gossypium/metabolismo , Ligação de Hidrogênio , Hidrólise , Cinética , Simulação de Dinâmica Molecular , Ligação Proteica , Trichoderma/químicaRESUMO
Efficient deconstruction of cellulosic biomass to fermentable sugars for fuel and chemical production is accomplished by a complex mixture of cellulases, hemicellulases, and accessory enzymes (e.g., >50 extracellular proteins). Cellulolytic enzyme mixtures, produced industrially mostly using fungi like Trichoderma reesei, are poorly characterized in terms of their protein composition and its correlation to hydrolytic activity on cellulosic biomass. The secretomes of commercial glycosyl hydrolase-producing microbes was explored using a proteomics approach with high-throughput quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we show that proteomics-based spectral counting approach is a reasonably accurate and rapid analytical technique that can be used to determine protein composition of complex glycosyl hydrolase mixtures that also correlates with the specific activity of individual enzymes present within the mixture. For example, a strong linear correlation was seen between Avicelase activity and total cellobiohydrolase content. Reliable, quantitative and cheaper analytical methods that provide insight into the cellulosic biomass degrading fungal and bacterial secretomes would lead to further improvements toward commercialization of plant biomass-derived fuels and chemicals.