Project Details
Projekt
Biogenesis of chitin matrices across scales in yeast and insect
Applicants
Luca Bertinetti, Ph.D.; Dr. Simone Mattei
Subject Area
Structural Biology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 525894472
Complex carbohydrates are important biopolymers fulfilling a myriad of different biochemical and structural functions across all kingdoms of life. Chitin is one of the two most abundant biopolymers on earth and is an essential polymers in the cell walls of fungi and the exoskeleton of arthropods, the largest most diverse animal phylum. Chitin is a linear polysaccharide of N-acetyl glucosamine (GlcNAc, chitin), and is prone to self-associate into semi-crystalline fibrillar structures that can be integrated with other polymers to create specialized biomaterials. Chitin is found in different organisms in its alpha or beta allomorph, in which polymer chains are arranged anti parallel or parallel, respectively, leading to materials with varying physical properties. Furthermore, post-synthesis the chitin polymer is modified by chitin deacetylases and chitinases, an essential processes that is crucial for further assembly. Despite many years of study, the molecular and cellular pathways leading to assembled cell wall or cuticle (apical extra-cellular matrix) are still unknown. We seek to characterize chitin biosynthesis and organization on a molecular and mechanistic level across scales in two of the most important chitin-producing groups, yeast and insects. To that end we will (1) determine the molecular structure of chitin synthase (CHS) from yeast and insects, and their chitin synthesis pathway within a heterologous system, using cryo-electron microscopy and cellular tomography. (2) determine the dynamic of CHS in vivo in insect cells and tissues using super-resolution live imaging methodologies. (3) determine the cellular pathway of chitin-protein fiber co-assembly and orientation using volume imaging with nanometer resolution. (4) Establish methodological workflows that allow determination of molecular structure of chitin synthase and assembly in situ, using focused ion beam/scanning electron microscopy and cryo-electron tomography. The project combines method development for state-of the art cryo-electron tomography and correlative light and electron microscopy, as one of the major goals of SPP 2416 “Analyzing and utilizing CodeChi", while at the same time strives towards a better understanding of the fundamental processes of writing and enacting CodeChi. Because chitin is both absent in humans and physiologically essential for many pathogens, chitin biosynthesis and assembly qualify as attractive targets for the development of novel pesticides and antimicrobial agents. Determining the molecular and mechanistic basis underlying the different modes of chitin fiber assembly will provide the molecular basis to target this Achilles’ heel in the development of many pathogens.
DFG Programme
Priority Programmes
Co-Investigator
Professorin Yael Politi, Ph.D.
