High-resolution archaellum structure reveals a conserved metal-binding site
Vladimir A Meshcheryakov1, Satoshi Shibata1, Makoto Tokoro Schreiber1
1Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Kunigami, Okinawa, Japan.
EMBO Reports
|March 23, 2019
Summary
Archaella, the archaeal flagella, are primarily composed of FlaB1. A conserved metal-binding site in FlaB1 is crucial for maintaining archaellum filament integrity, as revealed by structural and biochemical analyses.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Archaella enable archaeal motility but differ structurally and evolutionarily from bacterial flagella.
- Understanding archaellum assembly and stability requires detailed molecular insights.
Purpose of the Study:
- To elucidate the molecular structure and composition of Methanococcus archaella.
- To identify key components and stabilizing factors of the archaellum.
Main Methods:
- X-ray crystallography of Methanocaldococcus jannaschii FlaB1.
- Cryo-electron microscopy (cryo-EM) of Methanococcus maripaludis archaella.
- Mass spectrometry and electron energy-loss spectroscopy.
Main Results:
- Determined the 1.5 Å crystal structure of FlaB1 and a 4 Å cryo-EM reconstruction of archaella.
- Identified FlaB1 as the predominant archaellum component.
- Discovered N-linked glycosylation and a conserved metal-binding site in FlaB1.
- Validated the metal-binding site's necessity for filament integrity in vitro.
Conclusions:
- Archaella are mainly composed of FlaB1, with a conserved metal-binding site essential for filament stability.
- Structural and biochemical data provide a foundation for understanding archaellum function and evolution.
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