4PXT: Structural Basis For The Assembly Of The Mitotic Motor Kinesin-5 Into Bipolar Tetramers

Chromosome segregation during mitosis depends upon Kinesin-5 motors, which display a conserved, bipolar homotetrameric organization consisting of two motor dimers at opposite ends of a central rod. Kinesin-5 motors crosslink adjacent microtubules to drive or constrain their sliding apart, but the structural basis of their organization is unknown. In this study, we report the atomic structure of the bipolar assembly (BASS) domain that directs four Kinesin-5 subunits to form a bipolar minifilament. BASS is a novel 26-nm four-helix bundle, consisting of two anti-parallel coiled-coils at its center, stabilized by alternating hydrophobic and ionic four-helical interfaces, which based on mutagenesis experiments, are critical for tetramerization. Strikingly, N-terminal BASS helices bend as they emerge from the central bundle, swapping partner helices, to form dimeric parallel coiled-coils at both ends, which are offset by 90 degrees . We propose that BASS is a mechanically stable, plectonemically-coiled junction, transmitting forces between Kinesin-5 motor dimers during microtubule sliding. DOI: http://dx.doi.org/10.7554/eLife.02217.001.
PDB ID: 4PXTDownload
MMDB ID: 119955
PDB Deposition Date: 2014/3/25
Updated in MMDB: 2014/05
Experimental Method:
x-ray diffraction
Resolution: 2.9  Å
Source Organism:
Similar Structures:
Biological Unit for 4PXT: tetrameric; determined by author and by software (PISA)
Molecular Components in 4PXT
Label Count Molecule
Proteins (4 molecules)
Bipolar Kinesin Krp-130(Gene symbol: Klp61F)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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