Characterization of the Neurospora crassa Galactosaminogalactan Biosynthetic Pathway

Journal Article · Tue Jul 23 00:00:00 UTC 2024 · Microorganisms

DOI: https://doi.org/10.3390/microorganisms12081509 · OSTI ID:2530377

Chatrath, Apurva ^[1]; Dey, Protyusha ^[1]; Greeley, Kevin ^[1]; Maciel, Gabriela ^[1]; Huang, Lei ^[2]; Heiss, Christian ^[2]; Black, Ian ^[2]; Azadi, Parastoo ^[2]; Free, Stephen J. ^[1]

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1. SUNY University at Buffalo, NY (United States)
2. University of Georgia, Athens, GA (United States)

The Neurospora crassa genome has a gene cluster for the synthesis of galactosaminogalactan (GAG). The gene cluster includes the following: (1) UDP-glucose-4-epimerase to convert UDP-glucose and UDP-N-acetylglucosamine to UDP-galactose and UDP-N-acetylgalactosamine (NCU05133), (2) GAG synthase for the synthesis of an acetylated GAG (NCU05132), (3) GAG deacetylase (/NCW-1/NCU05137), (4) GH135-1, a GAG hydrolase with specificity for N-acetylgalactosamine-containing GAG (NCU05135), and (5) GH114-1, a galactosaminidase with specificity for galactosamine-containing GAG (NCU05136). The deacetylase was previously shown to be a major cell wall glycoprotein and given the name of NCW-1 (non-GPI anchored cell wall protein-1). Characterization of the polysaccharides found in the growth medium from the wild type and the GAG synthase mutant demonstrates that there is a major reduction in the levels of polysaccharides containing galactosamine and N-acetylgalactosamine in the mutant growth medium, providing evidence that the synthase is responsible for the production of a GAG. The analysis also indicates that there are other galactose-containing polysaccharides produced by the fungus. Phenotypic characterization of wild-type and mutant isolates showed that deacetylated GAG from the wild type can function as an adhesin to a glass surface and provides the fungal mat with tensile strength, demonstrating that the deacetylated GAG functions as an intercellular adhesive. The acetylated GAG produced by the deacetylase mutant was found to function as an adhesive for chitin, alumina, celite (diatomaceous earth), activated charcoal, and wheat leaf particulates.

• Research Organization: University of Georgia, Athens, GA (United States)
• Sponsoring Organization: National Institutes of Health (NIH); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: SC0015662
• OSTI ID: 2530377
• Journal Information: Microorganisms, Journal Name: Microorganisms Journal Issue: 8 Vol. 12; ISSN 2076-2607
• Publisher: MDPICopyright Statement
• Country of Publication: United States
• Language: English