Protein Biophysics Laboratory, Department of Life Science, Rikkyo University
Welcome to the web page of Yasuyuki KATO-YAMADA at the Department of Life Science, Rikkyo University! Our study is focusing on the structure-function relationship of proteins, especially of ATP synthase.
Blue part represents epsilon subunit of F1-ATPase.
epsilon Subunit is thought to be a regulator of bacterial ATP synthase. One of our main research themes is to figure out the relationship between structure and function of epsilon subunit as the regulatator of ATP synthse.
In particular, we are interested in the role of the ATP binding, which we found, to the epsilon subunit.
We are also carrying out studies focusing on the physiological significance of the regulation of ATP synthase by the epsilon subunit.
Relationship betweeen epsilon and ADP inhibition.
There is a regulatory system common to all ATP synthases, which is called "ADP-inhibition." The ADP-inhibition is caused by the tightly bound ADP after ATP hydrolysis reaction. The relationship between ADP-inhibition and the inhibition by the epsilon subunit is obscure since both inhibit ATPase activity, make it difficult to distinguish which mode of the inhibition is responsible for the particular moment. We have shown that inhibition by the epsilon subunit counteracts ADP-inhibition by single-molecular and biochemical analyses.
Under certain conditions, ATPase and H+ pump uncouple.
We recently found that depending on the nucleotide binding state of epsilon subunit, the coupling between ATPase and H+ pumping is altered. Under certain conditions, the epsilon subunit works as the molecular "clutch." We have been trying to figure out the molecular mechanism of the uncoupling and its physiological significance.
Kadoya, F. et al. (2011) Biochem. J. 437, 135
We also have been studying about thermal stability of ferredoxin, high puressure tolerance of IPMDH and so on.