title: Crystal structure of Zen4 in the apo state reveals a missing conformation of kinesin.
abstract: Kinesins hydrolyse ATP to transport intracellular cargoes along microtubules. Kinesin neck linker (NL) functions as the central mechano-chemical coupling element by changing its conformation through the ATPase cycle. Here we report the crystal structure of kinesin-6 Zen4 in a nucleotide-free, apo state, with the NL initial segment (NIS) adopting a backward-docked conformation and the preceding α6 helix partially melted. Single-molecule fluorescence resonance energy transfer (smFRET) analyses indicate the NIS of kinesin-1 undergoes similar conformational changes under tension in the two-head bound (2HB) state, whereas it is largely disordered without tension. The backward-docked structure of NIS is essential for motility of the motor. Our findings reveal a key missing conformation of kinesins, which provides the structural basis of the stable 2HB state and offers a tension-based rationale for an optimal NL length to ensure processivity of the motor.
authors.affiliation: MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China.|School of Life Science, Tsinghua University, Beijing 100084, China.
authors.forename: Ruifang
authors.initials: R
authors.lastname: Guan
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Beijing 100101, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Qian Peter
authors.initials: QP
authors.lastname: Su
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Mickolajczyk
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Geng-Yuan
authors.identifier: 0000-0002-0103-4494
authors.initials: GY
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: William O
authors.initials: WO
authors.lastname: Hancock
authors.affiliation: State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Sun
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Beijing 100101, China.
authors.forename: Yongfang
authors.identifier: 0000-0003-1751-7201
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China.|School of Life Science, Tsinghua University, Beijing 100084, China.
authors.forename: Zhucheng
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry*; D017173:Caenorhabditis elegans / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004330:Drosophila; D031541:Fluorescence Resonance Energy Transfer; D016547:Kinesins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D009711:Nucleotides / Q000737:chemistry; D011487:Protein Conformation; D051381:Rats; D013194:Staining and Labeling
chemical_list: D001059:Apoproteins; D029742:Caenorhabditis elegans Proteins; D009711:Nucleotides; C114455:ZEN-4 protein, C elegans; D016547:Kinesins