J Integr Plant Biol. ›› 2019, Vol. 61 ›› Issue (2): 93-109.DOI: 10.1111/jipb.12700

• Cell and Developmental Biology • Previous Articles     Next Articles

Crystal structure of Arabidopsis thaliana RabA1a

Ji-Sook Yun1, Sung Chul Ha2, Shinae Kim1, Yeon-Gil Kim2, Hyeran Kim3* and Jeong Ho Chang1*   

  1. 1Department of Biology Education, Kyungpook National University, Daehak-ro 80, Daegu 41566, South Korea
    2Beamline Science Division, Pohang Accelerator Laboratory, Jigok-ro 127, Pohang 37673, South Korea
    3Department of Biological Sciences, Kangwon National University, Kangwondaehak-gil 1, Chuncheon 24341, South Korea

    Email: Jeong Ho Chang (jhcbio@knu.ac.kr; Dr. Chang is fully responsible for the distribution of all materials associated with this article); Hyeran Kim (ranny@kangwon.ac.kr)
  • Received:2018-05-15 Accepted:2018-07-11 Online:2018-07-16 Published:2019-02-01

Abstract: RabGTPase is a member of the Ras superfamily of small GTPases, which share a GTP-binding pocket containing highly conserved motifs that promote GTP hydrolysis. In Arabidopsis, the RabA group, which corresponds to the Rab11 group in animals, functions in the recycling of endosomes that control docking and fusion during vesicle transport. However, their molecular mechanisms remain unknown. In this study, we determined the crystal structures of the GDP-bound inactive form and both GppNHp- and GTP-bound active forms of RabA1a, at resolutions of 2.8, 2.6, and 2.6 A, respectively. A bound sulfate ion in the active site of the GDP-bound structure stabilized Switch II by bridging the interaction between a magnesium ion and Arg74. Comparisons of the two states of RabA1a with Rab11 proteins revealed clear differences in the Switch I and II loops. These results suggested that conformational change of the Switch regions of RabA1a, derived by GTP or GDP binding, could maintain subcellular membrane traffic through the specific interaction of effector molecules.

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