| 1. |
- Bezerra Lima Verde, Isabel, et al.
(författare)
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Effect of season on bovine seminal plasma proteins in Thailand
- 2020
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Ingår i: Journal of Thermal Biology. - : Elsevier BV. - 0306-4565. ; 90
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Tidskriftsartikel (refereegranskat)abstract
- Although season has been shown to affect bull sperm quality and fertility in some studies, the effect of season on seminal plasma proteins has not been examined. In the present study, seminal plasma proteins were analysed by Fast Protein Liquid Chromatography (FPLC), to separate the phosphorylcholine-binding proteins and heparin-binding proteins from the other proteins. Semen samples were collected from bulls in three seasons: winter, summer and the rainy season. Sperm quality was analysed by flow cytometry and computer assisted sperm analysis, and further aliquots of semen were used to prepare the seminal plasma for FPLC. Meteorological data were available from a location close to the bull station. There were slight differences in sperm kinematics between seasons, but other parameters of sperm quality were not different. Minor differences in the phosphorylcholine-binding proteins were detected according to season, being lower in summer than in winter or in the rainy season, although there were no changes in the heparin-binding proteins. Temperature, humidity and rainfall differed between winter and the rainy season, but no differences were observed between summer and the rainy season except in the temperature humidity index (THI). However, the THI was above the threshold indicative of heat stress in all seasons, which could explain why few seasonal differences in protein composition were detected in this study. Alternatively, the bulls could have been well-adapted to heat stress. In conclusion, there were only slight differences in bull sperm quality and seminal plasma proteins between seasons during this study.
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| 2. |
- Chen, Yang, et al.
(författare)
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Crystal structure of linoleate 13R-manganese lipoxygenase in complex with an adhesion protein.
- 2016
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Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 57:8, s. 1574-1588
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of 13R-manganese lipoxygenase (MnLOX) of Gaeumannomyces graminis (Gg) in complex with zonadhesin of Pichia pastoris was solved by molecular replacement. Zonadhesin contains β-strands in two subdomains. A comparison of Gg-MnLOX with the 9S-MnLOX of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved. The U-shaped active sites differ mainly due to hydrophobic residues of the substrate channel. The volumes and two hydrophobic side pockets near the catalytic base may sanction oxygenation at C-13 and C-9, respectively. Gly-332 of Gg-MnLOX is positioned in the substrate channel between the entrance and the metal center. Replacements with larger residues could restrict oxygen and substrate to reach the active site. C18 fatty acids are likely positioned with C-11 between Mn(2+)OH2 and Leu-336 for hydrogen abstraction and with one side of the 12Z double bond shielded by Phe-337 to prevent antarafacial oxygenation at C-13 and C-11. Phe-347 is positioned at the end of the substrate channel and replacement with smaller residues can position C18 fatty acids for oxygenation at C-9. Gg-MnLOX does not catalyze the sequential lipoxygenation of n-3 fatty acids in contrast to Mo-MnLOX, which illustrates the different configurations of their substrate channels.
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| 3. |
- Deori, Sourabh, et al.
(författare)
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Fast protein liquid chromatography profiles of seminal plasma proteins in young bulls: A biomarker of sperm maturity?
- 2021
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- Breeding companies want to use semen from bulls as soon as possible to take advantage of their desirable genetics. It takes several weeks for the sperm quality of young bulls to stabilize and for post-thaw sperm quality to become acceptable for artificial insemination. Seminal plasma proteins protect spermatozoa during cryopreservation; it may take some time for the seminal plasma protein profile to stabilize. The purpose of this study was to determine if the seminal plasma protein profile can be used as a marker of likely seminal maturity in young bulls. A comparison was made of the seminal plasma protein profile in the ejaculates of 10 bulls of 9-10 months old (Sample I), with the profiles from ejaculates taken from the same bulls at 13-16 months old (Sample II) using fast protein liquid chromatography. This is a method for separating classes of proteins according to their binding ability. The peak area and peak height of different classes of proteins did not differ significantly between the two samples for each bull, except for peak 5 (heparin-binding proteins) and total peak area (p<0.05). The heparinbinding protein peak height and area were significantly higher (p<0.05) in Sample II than in Sample I. In conclusion, levels of fertility associated heparin-binding proteins increase with age in young bulls and might serve as a biomarker of sperm maturity. .
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| 4. |
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| 5. |
- García-Murria, María-Jesús, et al.
(författare)
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Structural and functional consequences of the replacement of proximal residues Cys(172) and Cys(192) in the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase from Chlamydomonas reinhardtii.
- 2008
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Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 411:2, s. 241-247
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Tidskriftsartikel (refereegranskat)abstract
- Proximal Cys(172) and Cys(192) in the large subunit of the photosynthetic enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39) are evolutionarily conserved among cyanobacteria, algae and higher plants. Mutation of Cys(172) has been shown to affect the redox properties of Rubisco in vitro and to delay the degradation of the enzyme in vivo under stress conditions. Here, we report the effect of the replacement of Cys(172) and Cys(192) by serine on the catalytic properties, thermostability and three-dimensional structure of Chlamydomonas reinhardtii Rubisco. The most striking effect of the C172S substitution was an 11% increase in the specificity factor when compared with the wild-type enzyme. The specificity factor of C192S Rubisco was not altered. The V(c) (V(max) for carboxylation) was similar to that of wild-type Rubisco in the case of the C172S enzyme, but approx. 30% lower for the C192S Rubisco. In contrast, the K(m) for CO(2) and O(2) was similar for C192S and wild-type enzymes, but distinctly higher (approximately double) for the C172S enzyme. C172S Rubisco showed a critical denaturation temperature approx. 2 degrees C lower than wild-type Rubisco and a distinctly higher denaturation rate at 55 degrees C, whereas C192S Rubisco was only slightly more sensitive to temperature denaturation than the wild-type enzyme. X-ray crystal structures reveal that the C172S mutation causes a shift of the main-chain backbone atoms of beta-strand 1 of the alpha/beta-barrel affecting a number of amino acid side chains. This may cause the exceptional catalytic features of C172S. In contrast, the C192S mutation does not produce similar structural perturbations.
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| 6. |
- Gudmundsson, Mikael, et al.
(författare)
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Structural and functional studies of the glycoside hydrolase family 3 beta-glucosidase Cel3A from the moderately thermophilic fungus Rasamsonia emersonii
- 2016
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Ingår i: Acta Crystallographica Section D. - 2059-7983. ; 72:7, s. 860-870
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous fungus Hypocrea jecorina produces a number of cellulases and hemicellulases that act in a concerted fashion on biomass and degrade it into monomeric or oligomeric sugars. beta-Glucosidases are involved in the last step of the degradation of cellulosic biomass and hydrolyse the beta-glycosidic linkage between two adjacent molecules in dimers and oligomers of glucose. In this study, it is shown that substituting the beta-glucosidase from H. jecorina (HjCel3A) with the beta-glucosidase Cel3A from the thermophilic fungus Rasamsonia emersonii (ReCel3A) in enzyme mixtures results in increased efficiency in the saccharification of lignocellulosic materials. Biochemical characterization of ReCel3A, heterologously produced in H. jecorina, reveals a preference for disaccharide substrates over longer gluco-oligosaccharides. Crystallographic studies of ReCel3A revealed a highly N-glycosylated three-domain dimeric protein, as has been observed previously for glycoside hydrolase family 3 beta-glucosidases. The increased thermal stability and saccharification yield and the superior biochemical characteristics of ReCel3A compared with HjCel3A and mixtures containing HjCel3A make ReCel3A an excellent candidate for addition to enzyme mixtures designed to operate at higher temperatures.
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| 7. |
- Haddad Momeni, Majid, et al.
(författare)
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Expression, crystal structure and cellulase activity of the thermostable cellobiohydrolase Cel7A from the fungus Humicola grisea var. thermoidea
- 2014
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Ingår i: Acta Crystallographica Section D: Biological Crystallography. - 0907-4449 .- 1399-0047. ; 70, s. 2356-2366
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Tidskriftsartikel (refereegranskat)abstract
- Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) play a key role in biomass recycling in nature. They are typically the most abundant enzymes expressed by potent cellulolytic fungi, and are also responsible for the majority of hydrolytic potential in enzyme cocktails for industrial processing of plant biomass. The thermostability of the enzyme is an important parameter for industrial utilization. In this study, Cel7 enzymes from different fungi were expressed in a fungal host and assayed for thermostability, including Hypocrea jecorina Cel7A as a reference. The most stable of the homologues, Humicola grisea var. thermoidea Cel7A, exhibits a 10 degrees C higher melting temperature (T-m of 72.5 degrees C) and showed a 4-5 times higher initial hydrolysis rate than H. jecorina Cel7A on phosphoric acid-swollen cellulose and showed the best performance of the tested enzymes on pretreated corn stover at elevated temperature (65 degrees C, 24 h). The enzyme shares 57% sequence identity with H. jecorina Cel7A and consists of a GH7 catalytic module connected by a linker to a C-terminal CBM1 carbohydrate-binding module. The crystal structure of the H. grisea var. thermoidea Cel7A catalytic module (1.8 angstrom resolution; R-work and R-free of 0.16 and 0.21, respectively) is similar to those of other GH7 CBHs. The deviations of several loops along the cellulose-binding path between the two molecules in the asymmetric unit indicate higher flexibility than in the less thermostable H. jecorina Cel7A.
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| 8. |
- Hansson, Henrik, et al.
(författare)
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High-resolution structure of a lytic polysaccharide monooxygenase from Hypocrea jecorina reveals a predicted linker as an integral part of the catalytic domain
- 2017
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 292, s. 19099-19109
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Tidskriftsartikel (refereegranskat)abstract
- For decades, the enzymes of the fungus Hypocrea jecorina have served as a model system for the breakdown of cellulose. Three-dimensional structures for almost all H. jecorina cellulose-degrading enzymes are available, except for HjLPMO9A, belonging to the AA9 family of lytic polysaccharide monooxygenases (LPMOs). These enzymes enhance the hydrolytic activity of cellulases and are essential for cost-efficient conversion of lignocellulosic biomass. Here, using structural and spectroscopic analyses, we found that native HjLPMO9A contains a catalytic domain and a family-1 carbohydrate-binding module (CBM1) connected via a linker sequence. A C terminally truncated variant of HjLPMO9A containing 21 residues of the predicted linker was expressed at levels sufficient for analysis. Here, using structural, spectroscopic, and biochemical analyses, we found that this truncated variant exhibited reduced binding to and activity on cellulose compared with the full-length enzyme. Importantly, a 0.95- resolution X-ray structure of truncated HjLPMO9A revealed that the linker forms an integral part of the catalytic domain structure, covering a hydrophobic patch on the catalytic AA9 module. We noted that the oxidized catalytic center contains a Cu(II) coordinated by two His ligands, one of which has a His-brace in which the His-1 terminal amine group also coordinates to a copper. The final equatorial position of the Cu(II) is occupied by a water-derived ligand. The spectroscopic characteristics of the truncated variant were not measurably different from those of full-length HjLPMO9A, indicating that the presence of the CBM1 module increases the affinity of HjLPMO9A for cellulose binding, but does not affect the active site.
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| 9. |
- Hansson, Henrik, et al.
(författare)
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Oxygen Activation by Cu LPMOs in Recalcitrant Carbohydrate Polysaccharide Conversion to Monomer Sugars
- 2018
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 118, s. 2593-2635
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Forskningsöversikt (refereegranskat)abstract
- Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes, which is evidenced by the established and emerging markets for products derived from these natural polymers. In many cases, this is achieved via industrial processes that use enzymes to break down carbohydrates to monomer sugars. One of the major challenges facing large-scale industrial applications utilizing natural carbohydrate polymers is rooted in the fact that naturally occurring forms of starch, cellulose, and chitin can have tightly packed organizations of polymer chains with low hydration levels, giving rise to crystalline structures that are highly recalcitrant to enzymatic degradation. The topic of this review is oxidative cleavage of carbohydrate polymers by lytic polysaccharide monooxygenases (LPMOs). LPMOs are copper-dependent enzymes (EC 1.14.99.53-56) that, with glycoside hydrolases, participate in the degradation of recalcitrant carbohydrate polymers. Their activity and structural underpinnings provide insights into biological mechanisms of polysaccharide degradation.
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| 10. |
- Herneke, A., et al.
(författare)
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Protein Nanofibrils for Sustainable Food-Characterization and Comparison of Fibrils from a Broad Range of Plant Protein Isolates
- 2021
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Ingår i: ACS Food Science and Technology. - : American Chemical Society (ACS). - 2692-1944. ; 1:5, s. 854-864
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Tidskriftsartikel (refereegranskat)abstract
- Protein nanofibrils (PNFs) from plant-based protein sources have great potential for use in new sustainable food applications or biobased materials. Plant-based proteins from seven different sources (fava bean, mung bean, lupin, oat, rapeseed, soybean, and potato) were evaluated here for their ability for forming PNFs and compared with whey protein PNFs. Formation of PNFs was studied under incubation at acidic conditions (pH 2) and heat (85-90 °C) for 24-96 h. Presence of PNFs was detected using thioflavin T, circular dichroism spectroscopy, Fourier-transform infrared spectroscopy, and atomic force microscopy. The results showed that all plant-based proteins were able to form PNFs. For some of the plant protein isolates in this study, nanofibril formation is reported for the first time. We also describe and compare the distinct features associated with each protein source and the morphological alterations of the nanoscale structures. Finally, we describe how PNF production can be enhanced by purifying the fibril-forming protein component. Taken together, our study suggests that the structural and functional variation within plant protein nanofibrils can be exploited in future scaled-up food or material applications.
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