Professor Ken Yokoyama

Area and Subject Taught Membrane Bioenergetics
Research Theme(s) Molecular mechanism of energy converted enzymes
Academic Degrees Doctor of Science, Tokyo Institute of Technology
Keywords for Research Field ATP, V-ATPase, Rotary motor, aging
Office Phone Number 81-75-705-3043

Research Overview

The focus of our laboratory is on both understanding molecular mechanism of energy conversion enzymes and relationship between energy metabolism and aging/longevity. The role of energy is fundamental to central phenomenon of organisms, e.g., growth, development, metabolism, and aging. Life is dependent on energy transformations; living organisms survive because of exchange of energy within and without. In all living organisms, adenosine 5’-triphosphate (ATP) is used as a ubiquitous energy currency, as well as an intra- and extra-cellular signaling molecule. ATP is predominantly generated by oxidative phosphorylation in mitochondria, in which respiratory complex I to V exist. Complex V, termed as ATP synthase, is a rotary molecular motor which converts chemical energy to rotation of central shaft apparatus, vice versa. Our focus is both on understanding detailed structure of complex I and an energy conversion mechanism of rotary molecular motor. We hope to know how these enzymes convert chemical energy to rotation of shaft or vectorial ion transport across the membranes. On the other hand, bioenergetics is deeply related on aging. Some mutants of respiratory enzymes in mitochondria increase the life span in some animals, such as nematodes and fl ies. We have started the studies on relationship between energy metabolism and aging using bio-imaging technique for ATP in nematode, Caenorhabditis elegans.

Notable Publications and Works in the Last Three Years

  1. Kishikawa J., Nakanishi A., Furuike S., Tamakoshi M., and *Yokoyama K. (2014) Molecular basis of ADP inhibition of VoV1. J.Biol.Chem. 289 403-412 .
  2. Kishikawa J., Ibuki T., Nakamura S., Nakanishi A., Minamino T., Miyata T., Namba K., Konno H., Ueno H., Imada K., *Yokoyama K. (2013) Common evolutionary origin for the rotor domain of rotary ATPases and Flagellar protein export apparatus. PLos One 8: e64695
  3. Tani K., Arthur C., Tamakoshi M., Yokoyama K., Mitsuoka K., Fujiyoshi Y., Gerle C. (2013) Visualization of Two distinct states of disassembly in the bacterial V-ATPase from Thermus thermophilus. Microscopy 62: 467-474
  4. Tritom NE., Okuno D., Nakano M., Yokoyama K., *Noji H. (2012) Mechanical Modulation of ATP-Binding Affinity of V1-ATPase. J. Biol. Chem. 288: 619-623
  5. Uner N. E., Nishikawa Y., Okuno D., Nakano M., Yokoyama K., Noji H. (2012) Single-molecule analysis of inhibitory pausing states of V1-ATPase. J. Biol. Chem. 287: 28327-28335
  6. Kishikawa J., *Yokoyama K. (2012) Reconstitution of Vacuolar type rotary H+-ATPase/synthase from Thermus thermophilus. J. Biol. Chem. 287: 24597-24603 2012 best of JBC paper
  7. Furuike S., Nakano M., Adachi K., Noji H., Kinosita K. Jr., *Yokoyama K. (2011) Resolving stepping rotation in Thermus thermophilus H+-ATPase/synthase with an essentially drag free probe. Nat. Commun. 2: 233-239
  8. Maher M. J., Akimoto S., Iwata M., Nagata K., Hori Y., Yoshida M., Yokoyama S., Iwata S., *Yokoyama K. (2009) Crystal structure of A3B3 complex of V-ATPase from Thermus thermophilus. EMBO J. 28: 3771-3779
  9. Kanno R., Koike-Takeshita A., Yokoyama K., Taguchi H., *Mitsuoka K. (2009) Cryo-EM structure of the native GroEL-GroES complex from Thermus thermophilus encapsulating substrate inside the cavity. Structure. 17: 287-293
  10. Takeda M., Ikeda C., Shimabukuro K., Yoshida M., *Yokoyama K. (2009) Mechanism of inhibition of Tributyltin chloride of the V type Molecular Motor. Biophys. J. 96: 1210-1217