Identification of proteins capable of metal reduction from the proteome of the Gram‐positive bacterium D esulfotomaculum reducens MI ‐1 using an NADH ‐based activity assay
Summary Understanding of microbial metal reduction is based almost solely on studies of G ram‐negative organisms. In this study, we focus on D esulfotomaculum reducens MI ‐1, a G ram‐positive metal reducer whose genome lacks genes with similarity to any characterized metal reductase. Using non‐den...
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Published in | Environmental microbiology Vol. 17; no. 6; pp. 1977 - 1990 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United Kingdom
Wiley-Blackwell
01.06.2015
|
Online Access | Get full text |
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Summary: | Summary
Understanding of microbial metal reduction is based almost solely on studies of
G
ram‐negative organisms. In this study, we focus on
D
esulfotomaculum reducens
MI
‐1, a
G
ram‐positive metal reducer whose genome lacks genes with similarity to any characterized metal reductase. Using non‐denaturing separations and mass spectrometry identification, in combination with a colorimetric screen for chelated
F
e(
III
)‐
NTA
reduction with
NADH
as electron donor, we have identified proteins from the
D
. reducens
proteome not previously characterized as iron reductases. Their function was confirmed by heterologous expression in
E
scherichia coli
. Furthermore, we show that these proteins have the capability to reduce soluble
C
r(
VI
) and
U
(
VI
) with
NADH
as electron donor. The proteins identified are
NADH
: flavin oxidoreductase (
D
red_2421) and a protein complex composed of oxidoreductase flavin adenine dinucleotide/
NAD
(
P
)‐binding subunit (
D
red_1685) and dihydroorotate dehydrogenase 1B (
D
red_1686).
D
red_2421 was identified in the soluble proteome and is predicted to be a cytoplasmic protein.
D
red_1685 and
D
red_1686 were identified in both the soluble as well as the insoluble protein fraction, suggesting a type of membrane association, although
PSORTb
predicts both proteins are cytoplasmic. This study is the first functional proteomic analysis of
D
. reducens
and one of the first analyses of metal and radionuclide reduction in an environmentally relevant
G
ram‐positive bacterium. |
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Bibliography: | USDOE |
ISSN: | 1462-2912 1462-2920 |
DOI: | 10.1111/1462-2920.12673 |