Distinct filament morphology and membrane tethering features of the dual FtsZs in Odinarchaeota

Abstract

The deep-branching Asgard archaea have emerged as a model to study Eukaryogenesis as they harbor homologs of many of the major eukaryotic protein families. In this study, we use Candidatus Odinarchaeota FtsZs as representatives to understand the probable origin, evolution, and assembly of the FtsZ-Tubulin protein superfamily in Asgard archaea. We have performed a comparative analysis of the biochemical properties and cytoskeletal assembly of FtsZ1 and FtsZ2, the two FtsZ isoforms in the Odinarchaeota metagenome. Our electron microscopy analysis reveals that OdinFtsZ1 assembles into curved single protofilaments, while OdinFtsZ2 forms stacked spiral ring-like structures. Upon sequence analysis, we identified an N-terminal amphipathic helix in OdinFtsZ1, which mediates direct membrane tethering. In contrast, OdinFtsZ2 is recruited to the membrane by the membrane-anchor OdinSepF via OdinFtsZ2s C-terminal tail. Overall, we report the presence of two distant evolutionary paralogs of FtsZ in Odinarchaeota, with distinct filament assemblies and differing modes of membrane targeting mechanisms, namely direct vs SepF-mediated membrane binding. Our findings highlight the diversity of FtsZ proteins in the transitional archaeal phylum Odinarchaeota, providing valuable insights into the evolution and differentiation of tubulin family proteins.