Diversity and functional analysis of proteorhodopsin in marine Flavobacteria
Summary Proteorhodopsin (PR) genes are widely distributed among marine prokaryotes and functions as light‐driven proton pump when expressed heterologously in Escherichia coli, suggesting that light energy passing through PR may be substantial in marine environment. However, there are no data on PR p...
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Published in | Environmental microbiology Vol. 14; no. 5; pp. 1240 - 1248 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Publishing Ltd
01.05.2012
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Subjects | |
Online Access | Get full text |
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Summary: | Summary
Proteorhodopsin (PR) genes are widely distributed among marine prokaryotes and functions as light‐driven proton pump when expressed heterologously in Escherichia coli, suggesting that light energy passing through PR may be substantial in marine environment. However, there are no data on PR proton pump activities in native marine bacteria. Here, we demonstrate light‐driven proton pump activity (c. 124 H+ PR−1 min−1) in recently isolated marine Flavobacteria. Among 75 isolates, 38 possessed the PR gene. Illumination of cell suspensions from all eight tested strains in five genera triggered marked pH drops. The action spectrum of proton pump activity closely matched the spectral distribution of the sea surface green light field. Addition of hydroxylamine to a solubilized membrane fraction shifted the spectrum to a form characteristic of PR photobleached into retinal oxime, indicating that PRs in flavobacterial cell membranes transform the photon dose in incident radiation into energy in the form of membrane potential. Our results revealed that PR‐mediated proton transport can create the sufficient membrane potential for the ATP synthesis in native flavobacterial cells. |
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Bibliography: | ark:/67375/WNG-2QLZRTS3-W istex:472D80D3328B567DAD0898EE341617E9227E4107 ArticleID:EMI2702 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1462-2912 1462-2920 |
DOI: | 10.1111/j.1462-2920.2012.02702.x |