FGB1 as a New Molecular Probe for Fungi
Non-destructive detection of β-1,6-glycosidic bounds in complex samples
Chitin is the best studied fungal microbe-associated molecular pattern (MAMPs). However, the most abundant building block of fungal cell walls is β-glucan, which makes up 50-60% of the dry weight. Whereas β-1,3-glucose chains can also be found in the cell wall of plants, polymers containing β-1,6-glycosidic bonds have only been found in the cell wall of fungi and members of the phylum Stramenopiles, such as in some genera of oomycetes. There it is proposed that the β-1,6-glycosidic bonds are responsible to connect glucan chains and link these also to chitin.
The multibranched β-glucans can be firmly bound to the cell wall or loosely bound and accumulate around the fungus as slime or gelatinous material. The inventors identified a novel type of lectin domain in a so far uncharacterised fungal protein – further referred to as FGB1 (fungal glycan binding 1). FGB1 specifically binds β-1,6-glycosidic bonds with high affinity. A conjugate of FGB1 and a detectable label can be used as a tool to detect the presence of microorganisms having β-1,6-glycosidic bounds.
- β-1,6-glucan is an important fungal MAMP
- Easy detection of microbes and glucans containing β1,6 glycosidic linkages in complex mixtures
- Useful as a research tool for histochemical and flow cytometric applications and for localizing glycoproteins
- Useful for medical diagnostic purposes
- Fusion proteins might be useful in medical or agricultural applications
- Easy application
Some lectins like WGA, which detects chitin (and other carbohydrate polymers), are used as versatile probes for detecting glycoconjugates in histochemical and flow cytometric applications and for localizing glycoproteins in gels. So far, none of the lectins characterised bind specifically to β-1,6-glycosidic bounds. Therefore, FGB1 is a valuable tool to study fungal and oomycete cell wall development and composition.
As FGB1 represents a tool to detect the presence of microbes in complex mixtures, it could also function for the diagnosis of human infections caused by fungal and oomycete pathogens.
In addition, the biochemical properties of FGB1 suggest that it could be an ideal platform to engineer molecules with specific and novel carbohydrate binding properties.
It is imaginable that a fusion protein of FGB1 and a fungicide would significantly increase the effect of such fungicide as it would stick the effector to the microbe.
The detection of β-1,6-glycosidic bounds with a conjugate of FGB1 and a detectable label has successfully been tested on different types of fungi in a variety of complex samples.
On behalf of the University of Cologne, PROvendis offers access to rights for commercial use as well as the opportunity for further co-development. We will be pleased to inform you about the current patent status.
Publikationen & Verweise
Fesel, P. and Zuccaro, A. (2016) β-glucan: Crucial component of the fungal cell wall and elusive MAMP in plants. Fungal Genetics and Biology. 90, 53-60
Wawra, S. et al (2016) The novel fungal specific β-glucan binding lectin FGB1 alters susceptibility to cell wall stress and prevents glucan-triggered immunity in plants. Nature Communications. 13188, DOI: 10.1038
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Stichworteß-1,6, β-glucan, β-glycosidic bond, MAMP, fungus, fungi, chitin, WGA, lectin, β-1,3, oomycetes, detection, diagnostic, human infection, fungicide, histochemical, flow cytometric, research tool, localizing, agricultur