annual-biotechnology-2017-scientifictracks

7 / 21

Page 21
Notes:
alliedacademies
August 17-18, 2017 | Toronto, Canada
ANNUAL BIOTECHNOLOGY CONGRESS
Ann Biol Sci, 2017
ISSN: 2348-1927
New insight into the functional switching of 2-cys peroxiredoxin revealed by high-speed atomic force
microscopy
Hiroki Konno, Takamitsu Haruyama, Takayuki Uchihashi, Yutaro Yamada, Noriyuki Kodera and Toshio Ando
Kanazawa University, Japan
P eroxiredoxin (Prx) is an ubiquitous antioxidant enzyme
that reduces reactive oxygen species (ROS) such as
hydrogen peroxide, organic peroxide and peroxynitrite.
Prxs are classified into typical 2-Cys Prx, atypical 2-Cys Prx
and 1-Cys Prx based on the number of cysteine residues
and the catalytic mechanisms for their peroxidase activity.
The function of 2-Cys peroxiredoxins (2Cys-Prxs) can be
converted alternatively from peroxidases to molecular
chaperones. This conversion has been reported to occur by
the formation of high molecular weight (HMW) complexes
upon overoxidation of or ATP/ADP binding to 2-Cys Prxs
that appear in electron micrographs as spheres, decameric
rings, double-stacked decamers or further stacked filaments.
However, the entity responsible for the chaperone function
is under debate. We employed the high-speed atomic force
microscopy (HS-AFM) to investigate correlation between
structure of HMW complex of human PrxII (hPrxII) and its
chaperone activity. By the HS-AFM observation, we found
that upon binding to phospholipids dimeric human 2-Cys PrxII
(hPrxII) is assembled to small oligomers with full chaperone
and null peroxidase activities. Spherical HMW complexes are
formed, only when phospholipids is bound to overoxidized
or ATP/ADP-bound hPrxII. The spherical HMW complexes
are lipid vesicles covered with hPrxII oligomers arranged in a
hexagonal lattice pattern. Thus, these lipids can be supplied
by increased membrane trafficking under oxidative stress,
are essential for the structural and functional switch of hPrxII
and possibly most 2-Cys Prxs.
Speaker Biography
Hiroki Konno has completed his PhD from Tokyo Institute of Technology (Tokyo Tech) in
2002 and Post-doctoral studies from Tokyo Tech. In 2006, he joined chemical resources
laboratory, Tokyo Tech, as an Assistant Professor. In the above period, he has studied
regulation mechanism of rotary motor, ATP synthase, with biochemical and biophysical
methods. Since November 2011, he has been with the Imaging Research Division of
Bio-AFM Frontier Research Center, Kanazawa University, where he is currently an
Associate Professor. His current research interests include observing protein molecule
in dynamic action with HS-AFM.
e:
Hiroki Konno et al., Ann Biol Sci, 2017, 5:3
DOI: 10.21767/2348-1927-C1-002