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ID 39968
file
creator
Yamamoto, Sohei
Michibata, Hitoshi
subject
Transition metal
Disulfide bonds
Vanadium
Reductase
Ascidians
NDC
Biology
abstract
Ascidians (tunicates or sea squirts) accumulate extremely high levels of vanadium as the reduced form V(III) in extremely acidic vacuoles in their blood cells. Several key proteins related to vanadium accumulation have been isolated from vanadium-rich ascidians and their physiological functions characterized. Of these, vanabins are small, cysteine-rich proteins that have been identified only in vanadium-rich ascidians. Our previous study revealed that Vanabin2 can act as a V(V)-reductase. The current study examines the role of cysteine and several other amino acid residues of Vanabin2 in V(V)-reduction. When all eighteen cysteine residues of Vanabin2 were substituted with serine residues, the V(V)-reductase activity was lost. Substitutions of three, structurally clustered cysteines in three different regions resulted in a moderate decrease in reductase activity, suggesting that more than a single cysteine pair is responsible for the V(V)-reductase activity of Vanabin2. Mutations in the V(IV)-binding domains caused either an increase or decrease in activity but no mutation caused the complete loss of activity. These results suggest that some pairs, but more than a single pair, of cysteine residues are necessary for the V(V)-reductase activity of Vanabin2.
journal title
Inorganica Chimica Acta
volume
Volume 420
start page
47
end page
52
date of issued
2014-08-24
publisher
Elsevier B.V.
issn
0020-1693
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2013 Elsevier B.V. All rights reserved.
relation
This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
relation is version of
http:doi.org/10.1016/j.ica.2013.11.023
department
Graduate School of Science