Nuleotide sugar photoaffinity analogs have proven to be useful in the identification and characterization of glycosyltransferases. A radioenzymatic synthesis of [32P]5-azido-UDP-N-acetylglucosamine has been accomplished using 5-azido-UTP, [gamma-32P]ATP, porcine N-acetylgalactosamine kinase, and Escherichia coli UDP-N-acetylglucosamine pyrophosphorylase, GlmU. This general enzymatic scheme was useful for the synthesis of [32P]5-azido-UDP-N-acetylgalactosamine and high-specific-activity [3H] or [32P]UDP-N-acetylhexosamines. A new chemical synthesis method for generating 5-azido-uridine compounds was also developed. [32P]5-Azido-UDP-N-acetylglucosamine was functionally characterized using different soluble and membrane-associated glycosyltransferases which utilize UDP-GlcNAc as a substrate. Site-specific photoincorporation was observed for partially purified GlmU and porcine UDP-GlcNAc pyrophosphorylase. The photoprobe also effectively photoincorporated into the alpha- and beta-subunits of purified bovine UDP-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase. Lastly, the photoprobe was also effective at photolabeling Streptococcus pyogenes hyaluronate synthase in membrane preparations.
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http://dx.doi.org/10.1006/abio.1998.2600 | DOI Listing |
Sci Adv
January 2025
Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
RSC Adv
November 2024
Department of Developmental Biology, Washington University in St. Louis 660 S. Euclid Ave. St. Louis MO 63110 USA
The endogenous neurosteroids dehydroepiandrosterone sulfate (DHEAS) and pregnenolone sulfate (PS) are allosteric modulators of γ-aminobutyric acid type A (GABA) and -methyl-d-aspartate (NMDA) type glutamate receptors. Analogues of these endogenous steroid sulfates can be either positive or negative allosteric modulators (PAMs or NAMs, respectively) of these receptors, but there is limited information about the steroid-protein binding interactions that mediate these effects and photoaffinity labeling reagents (PALs) of sulfated steroids have not been reported previously. The synthesis of a panel of ten sulfated steroid analogues containing a diazirine group, five of which also contain an alkyne group for click chemistry reactions, for use in photoaffinity labeling studies to identify binding sites for steroid sulfates that are either positive or negative allosteric modulators is reported.
View Article and Find Full Text PDFNeurosteroids positively modulate GABA receptor (GABAR) channel activity by binding to a transmembrane domain intersubunit site. Using photo-affinity labeling and an ELIC-αGABAR chimera, we investigated the impact of mutations within the intersubunit site on neurosteroid binding. These mutations reduce neither photolabeling within the intersubunit site nor competitive prevention of labeling by allopregnanolone.
View Article and Find Full Text PDFACS Chem Biol
November 2024
RA Capital Ventures, Boston, Massachusetts 02116, United States.
Mutations in creatine transporter SLC6A8 cause creatine transporter deficiency (CTD), which is responsible for 2% of all cases of X-linked intellectual disability. CTD has no current treatments and has a high unmet medical need. Inspired by the transformational therapeutic impact of small molecule "correctors" for the treatment of cystic fibrosis, which bind to mutated versions of the CFTR ion channel to promote its trafficking to the cell surface, we sought to identify small molecules that could stabilize SLC6A8 as a potential treatment for CTD.
View Article and Find Full Text PDFChemistry
December 2024
Chemical Research Laboratories, Nissan Chemical Corporation, 10-1 Tsuboi-Nishi 2-chome, Funabashi, Chiba, Japan.
DNA-encoded library (DEL) technology is a crucial tool in pharmaceutical research, rapidly identifying compounds that bind to a target of interest from an extensive pool of compounds. In this study, we propose a new method for generating single-stranded DELs (ssDELs) with compounds at the 3' end. The introduction of uniquely designed hairpin-shaped headpieces containing deoxyuridine (NC-HP) and the use of a cleavage enzyme facilitate the conversion from double-stranded DELs (dsDELs) to such ssDELs.
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