A polysaccharide (PPS) in peanut sediment of aqueous extraction process was obtained at pH4.0, purified via anion-exchange chromatography. The composition, chain conformation and rheological properties were investigated. PPS mainly consisted of arabinose, galacturonic acid, xylose, and rhamnose. The intrinsic viscosity [η] was 0.71 dL/g in 0.1 M NaNO solution. The weight-average molar mass Mw and polydispersity index were 3.77 × 10 g/mol and 1.25, suggesting high homogeneity. The average radius of gyration (R), hydrodynamic radius (R), R/R ratio and conformation parameter v were 25.5, 18.2, 1.40 and 0.21, respectively, indicating compact coil chain conformation with branched structure. Molecular morphology revealed that PPS displayed chain shape comprised of spheres with a diameter range of 15-50 nm and apparent length of chains mainly ranged from 100 to 300 nm. The aggregation caused by molecular self-association enhanced with concentration increasing. Additionally, Newtonian behavior was observed at various concentrations. Increase in temperature effectively broke this behavior. 10.0 wt.% PPS possessed activation energy of 21.7 KJ/mol, was structured liquid and almost fitted Cox-Merz rule. These closely related with its conformation and molecular self-association behavior.
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http://dx.doi.org/10.1016/j.carbpol.2019.115410 | DOI Listing |
Mol Cell
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Ubiquitin Signalling Division, WEHI, Melbourne, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia. Electronic address:
The modification of proteins and other biomolecules with the small protein ubiquitin has enthralled scientists from many disciplines for decades, creating a broad research field. Ubiquitin research is particularly rich in molecular and mechanistic understanding due to a plethora of (poly)ubiquitin structures alone and in complex with ubiquitin machineries. Furthermore, due to its favorable properties, ubiquitin serves as a model system for many biophysical and computational techniques.
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College of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan, China; Collaborative Innovation Center of Food Production and Safety, Zhengzhou, Henan, China.
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Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, USA.
Discovered in 1994 in lesions of an AIDS patient, Kaposi's sarcoma-associated herpesvirus (KSHV) is a member of the gammaherpesvirus subfamily of the family, which contains a total of nine that infect humans. These viruses all contain a large envelope glycoprotein, glycoprotein B (gB), that is required for viral fusion with host cell membrane to initial infection. Although the atomic structures of five other human herpesviruses in their postfusion conformation and one in its prefusion conformation are known, the atomic structure of KSHV gB has not been reported.
View Article and Find Full Text PDFJ Am Chem Soc
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Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States.
In this Perspective, we highlight the emergence of target-oriented syntheses of complex molecules composed of Si-Si (oligosilanes) rather than C-C bonds. Saturated oligosilanes structurally resemble alkanes with respect to a tetrahedral geometry, a preference for a staggered conformation in linear chains, the ability to form stable small rings, and tetrahedral stereochemistry at asymmetrically functionalized Si centers. There are also critical differences, for example, differences in multiple bonding and the ability to form penta- and hexacoordinated structures, that mean that chemical reactivity and, in particular, rules for stereoselective synthesis do not cleanly translate from carbon to silicon.
View Article and Find Full Text PDFNucleic Acids Res
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Department of Biochemistry, University of Zurich, Winterthurerstrass 190, 8057 Zurich, Switzerland.
Type III clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) systems (type III CRISPR-Cas systems) use guide RNAs to recognize RNA transcripts of foreign genetic elements, which triggers the generation of cyclic oligoadenylate (cOA) second messengers by the Cas10 subunit of the type III effector complex. In turn, cOAs bind and activate ancillary effector proteins to reinforce the host immune response. Type III systems utilize distinct cOAs, including cyclic tri- (cA3), tetra- (cA4) and hexa-adenylates (cA6).
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