Project Details
Projekt
Structural and evolutionary comparison of the chloroplast translocon during streptophyte algae land colonization
Applicant
Dr. Jan Michael Schuller
Subject Area
Plant Biochemistry and Biophysics
Biochemistry
Structural Biology
Biochemistry
Structural Biology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 527846412
The evolution of a machinery that transports proteins across the two membranes separating the stroma of the organelle from the cytosol was crucial for the transition of a cyanobacterium endosymbiont to a plastid within a heterotrophic host. This machinery comprises a supercomplex of the translocon on the outer envelope of chloroplasts (TOC) and the translocon on the inner envelope of chloroplasts (TIC). This chloroplast translocon underwent significant changes during the evolution of streptophytes. Our objective is to understand whether changes in the preprotein import process were temporally associated with an increase in import efficiency along the evolutionary trajectory of land plant evolution. To accomplish this, we will evaluate import efficiency through in-vitro pre-protein translocation assays along the evolutionary lineage from green algae to land plants, by examining Streptophyta algae from KCC and ZCC clades, as well as bryophytes. Furthermore, by utilizing stalled-substrates and X-linking MS as well as computational modelling, we aim to identify proteins factors that enhanced the import efficiency during the evolution of land plants. Our in-vitro studies will be complemented with a top-down approach using in-situ cryo-electron tomography to answer the crucial question of how translocon complexes are organized structurally and spatially within the cellular context in selected streptophyta algae. Using this multi-scale integrative approach, we ultimately aim to establishing a correlation between import efficiency, translocon composition, structure and cellular organization. This will pinpoint the sequence of molecular adaptions that have taken place to increase chloroplast translocon efficiency, a pivotal feature in the evolution of charophyte freshwater algae, leading to their successful conquest of land.
DFG Programme
Priority Programmes
