The isolated paired helical filaments (PHF) that occur in the neurofibrillary tangles of Alzheimer's disease were assayed to determine if they contained N-acetyl-glucosamine and N-acetyl-galactosamine residues. The enzyme-linked lectin assay was used to detect their total content in the PHF preparation. The assay employed biotinylated Dolichos biflorus and wheat germ agglutinins and was developed with avidin-horseradish peroxidase. The total PHF preparation was shown to contain very little of these glycosyl groups compared to equal amounts of highly glycosylated control proteins. Colloidal gold-labeled lectins were used to study the PHF by electron microscopy to assess whether the minor amount of lectin binding in the total preparation was directly associated with the PHF. These studies showed no significant association of the colloidal gold-labeled lectins with the isolated filaments. We conclude that the PHF themselves contain few or no N-acetyl-glucosamine or N-acetyl-galactosamine residues.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/BF00294242 | DOI Listing |
J Chem Theory Comput
January 2025
Laboratory of Medicinal Chemistry, Rega Institute for Medicinal Research, Herestraat 49, Box 1030, Leuven B-3000, Belgium.
Synthetic nucleic acids, also defined as xenobiotic nucleic acids (XNAs), opened an avenue to address the limitations of nucleic acid therapeutics and the development of alternative carriers for genetic information in biotechnological applications. Two related XNA systems of high interest are the α-l-threose nucleic acid (TNA) and (3'-2') phosphonomethyl threosyl nucleic acid (tPhoNA), where TNAs show potential in antisense applications, whereas tPhoNAs are investigated for their predisposition toward orthogonal genetic systems. We present predictions on helical models of TNA and tPhoNA chemistry in homoduplexes and in complex with native ribose chemistries.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA.
DEAD-box RNA-dependent ATPases are ubiquitous in all domains of life where they bind and remodel RNA and RNA-protein complexes. DEAD-box ATPases with helicase activity unwind RNA duplexes by local opening of helical regions without directional movement through the duplexes and some of these enzymes, including Ded1p from Saccharomyces cerevisiae, oligomerize to effectively unwind RNA duplexes. Whether and how DEAD-box helicases coordinate oligomerization and unwinding is not known and it is unclear how many base pairs are actively opened.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
In DNA double helices, Hoogsteen (HG) base pairing is an alternative mode of Watson-Crick (WC) base pairing. HG bp has a different hydrogen bonding pattern than WC bp. We investigate here the binding energy of homeodomain proteins with a HG-DNA duplex, where DNA adopts a HG bp in its sequence.
View Article and Find Full Text PDFMicromachines (Basel)
January 2025
State Key Laboratory of Radio Frequency Heterogeneous Integration, Shanghai Jiao Tong University, Shanghai 200240, China.
On-chip gene synthesis has the potential to improve the synthesis throughput and reduce the cost exponentially. While there exist several microarray-based oligo synthesis technologies, on-chip gene assembly has yet to be demonstrated. This work introduces a novel on-chip DNA assembly method via dielectrophoresis (DEP) that can potentially be integrated with microarray-based oligo synthesis on the same chip.
View Article and Find Full Text PDFCRISPR-Cas12a is widely used for genome editing and biomarker detection since it can create targeted double-stranded DNA breaks and promote non-specific DNA cleavage after identifying specific DNA. To mitigate the off-target DNA cleavage of Cas12a, we previously developed a Cas12a variant (FnoCas12a ) by introducing double proline substitutions (K969P/D970P) in a conserved helix called the bridge helix (BH). In this work, we used cryogenic electron microscopy (cryoEM) to understand the molecular mechanisms of BH- mediated activation of Cas12a.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!