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ID 26921
file
creator
Kawakami, Norifumi
Amata, Yusuke
Kanamori, Kan
Gekko, Kunihiko
Michibata, Hitoshi
subject
Ascidian
Vanadium
Vanabin2
Redox
Thiol-disulfide exchange reaction
NDC
Biology
abstract
The unusual ascidian ability to accumulate high levels of vanadium ions at concentrations of up to 350 mM, a 107-fold increase over that found in seawater, has been attracting interdisciplinary attention for a century. Accumulated VV is finally reduced to VIII via VIV in ascidian vanadocytes. Reducing agents must therefore participate in the reduction. Previously, we identified a vanadium-binding protein, Vanabin2, in which all 18 cysteines form nine disulfide bonds. Here, we report that Vanabin2 is a novel vanadium reductase because partial cleavage of its disulfide bonds results in the reduction of VV to VIV. We propose that Vanabin2 forms a possible electron transfer cascade from the electron donor, NADPH, via glutathione reductase, glutathione, and Vanabin2 to the acceptor, and vanadium ions conjugated through thiol-disulfide exchange reactions.
journal title
Biochimica et Biophysica Acta. Proteins and Proteomics
volume
Volume 1794
issue
Issue 4
start page
674
end page
679
date of issued
2009-04
publisher
Elsevier B.V.
issn
1570-9639
ncid
publisher doi
pubmed id
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2009 Elsevier B.V.
relation is version of URL
http://dx.doi.org/10.1016/j.bbapap.2009.01.007
department
Graduate School of Science