Structure and Flexibility of the C-Ring in the Electromotor of Rotary FoF1-ATPase of Pea Chloroplasts
Autor(en): | Saroussi, Shai Schushan, Maya Ben-Tal, Nir Junge, Wolfgang Nelson, Nathan |
Stichwörter: | COLI ATP SYNTHASE; CRYSTAL-STRUCTURE; ELASTIC POWER TRANSMISSION; F-ATPASE; MECHANISM; Multidisciplinary Sciences; NA+-ATPASE; NORMAL-MODE ANALYSIS; PROTEIN; ROTOR RING; Science & Technology - Other Topics; VISCOELASTIC DYNAMICS | Erscheinungsdatum: | 2012 | Herausgeber: | PUBLIC LIBRARY SCIENCE | Journal: | PLOS ONE | Volumen: | 7 | Ausgabe: | 9 | Zusammenfassung: | A ring of 8-15 identical c-subunits is essential for ion-translocation by the rotary electromotor of the ubiquitous FOF1-ATPase. Here we present the crystal structure at 3.4 angstrom resolution of the c-ring from chloroplasts of a higher plant (Pisum sativum), determined using a native preparation. The crystal structure was found to resemble that of an (ancestral) cyanobacterium. Using elastic network modeling to investigate the ring's eigen-modes, we found five dominant modes of motion that fell into three classes. They revealed the following deformations of the ring: (I) ellipsoidal, (II) opposite twisting of the luminal circular surface of the ring against the stromal surface, and (III) kinking of the hairpin-shaped monomers in the middle, resulting in bending/stretching of the ring. Extension of the elastic network analysis to rings of different cn-symmetry revealed the same classes of dominant modes as in P. sativum (c(14)). We suggest the following functional roles for these classes: The first and third classes of modes affect the interaction of the c-ring with its counterparts in F-O, namely subunits a and bb'. These modes are likely to be involved in ion-translocation and torque generation. The second class of deformation, along with deformations of subunits gamma and epsilon might serve to elastically buffer the torque transmission between F-O and F-1. |
ISSN: | 19326203 | DOI: | 10.1371/journal.pone.0043045 |
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geprüft am 29.05.2024