An endogalactosaminidase has been purified 34-fold from the culture filtrate of Streptomyces griseus. This enzyme cleaves GalN-GalN linkages in oligogalactosaminoglycan, a galactosamine-rich oligosaccharide isolated from the culture filtrate of a Neurospora mutant. Since some or all of the GalN-GalN bonds in this molecule link positions 1 and 4, and are in the alpha-configuration, we are probably dealing with an endo-alpha-(1 leads to 4)-galactosaminidase, bu this characterization is only tentative because the few bonds cleaved by the enzyme could have a different structure. The enzyme is inactive towards N-acetyl-oligogalactosaminoglycan and chitosan. The endogalactosaminidase preparations also cleave high molecular weight galactosaminoglycan (obtained from Neurospora) into fragments greater than or equal to 10(4) daltons in molecular weight, and catalyze the release of Neurospora sporelings from the glass surfaces to which they are anchored. Galactosaminoglycan-cleaving and sporeling-releasing activities elute jointly from DEAE-cellulose columns. This observation provides further support for an earlier proposal that the sporelings are anchored to the glass by means of galactosaminoglycan molecules.
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bioRxiv
January 2025
Chemical and Biological Engineering - Iowa State University, 618 Bissell Rd, Ames, IA 50011.
Proteins can be rapidly prototyped with cell-free expression (CFE) but in most cases there is a lack of probes or assays to measure their function directly in the cell lysate, thereby limiting the throughput of these screens. Increased throughput is needed to build standardized, sequence to function data sets to feed machine learning guided protein optimization. Herein, we describe the use of fluorescent single-walled carbon nanotubes (SWCNT) as effective probes for measuring protease activity directly in cell-free lysate.
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January 2025
Institute of Plant Genetics and Biotechnology, Plant Science and Biodiversity Center, Slovak Academy of Sciences, Akademicka 2, P. O. Box 39A, 950 07, Nitra, Slovak Republic.
DbChitI-3, Drosera binata's acidic chitinase, peaks at pH 2.5 from 15 °C to 30 °C. Gene expression is stimulated by polysaccharides and suppressed by monosaccharide digestion, implying a feedback loop in its transcriptional regulation.
View Article and Find Full Text PDFIndian J Microbiol
December 2024
Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig, Egypt.
Fungal pathogens cause over a billion human infections annually, leading to more than 1.6 million deaths each year. The scarcity of available antifungal drugs intensifies the public health threat posed by human pathogenic fungal infections.
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December 2024
Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Avenue North, Seattle, WA, 98109, USA.
Griselimycin, a cyclic depsidecapeptide produced by Streptomyces griseus, is a promising lead inhibitor of the sliding clamp component of bacterial DNA polymerases (β-subunit of Escherichia coli DNA pol III). It was previously shown to inhibit the Mycobacterium tuberculosis β-clamp with remarkably high affinity and selectivity - the peptide lacks any interaction with the human sliding clamp. Here, we used a structural genomics approach to address the prospect of broader-spectrum inhibition, in particular of β-clamps from Gram-negative bacterial targets.
View Article and Find Full Text PDFNat Commun
November 2024
Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Terpenoids are the largest class of natural products, found across all domains of life. One of the most abundant bacterial terpenoids is the volatile odorant 2-methylisoborneol (2-MIB), partially responsible for the earthy smell of soil and musty taste of contaminated water. Many bacterial 2-MIB biosynthetic gene clusters were thought to encode a conserved transcription factor, named EshA in the model soil bacterium Streptomyces griseus.
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