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Integration of Temperature and Blue‐Light Sensing in Acinetobacter baumannii Through the BlsA Sensor
Author(s) -
Abatedaga Inés,
Valle Lorena,
Golic Adrián E.,
Müller Gabriela L.,
Cabruja Matías,
Morán Vieyra Faustino E.,
Jaime Paula C.,
Mussi María Alejandra,
Borsarelli Claudio D.
Publication year - 2017
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12760
Subject(s) - acinetobacter baumannii , biofilm , virulence , blue light , biophysics , chemistry , bacteria , biology , microbiology and biotechnology , physics , biochemistry , optoelectronics , pseudomonas aeruginosa , genetics , gene
Abstract BlsA is a BLUF photoreceptor present in Acinetobacter baumannii , responsible for modulation of motility, biofilm formation and virulence by light. In this work, we have combined physiological and biophysical evidences to begin to understand the basis of the differential photoregulation observed as a function of temperature. Indeed, we show that blsA expression is reduced at 37°C, which correlates with negligible photoreceptor levels in the cells, likely accounting for absence of photoregulation at this temperature. Another point of control occurs on the functionality of the BlsA photocycle itself at different temperatures, which occurs with an average quantum yield of photoactivation of the signaling state of 0.20 ± 0.03 at 15°C < T < 25°C, but is practically inoperative at T > 30°C, as a result of conformational changes produced in the nanocavity of FAD . This effect would be important when the photoreceptor is already present in the cell to avoid almost instantaneously further signaling process when it is no longer necessary, for example under circumstances of temperature changes possibly faced by the bacteria. This complex interplay between light and temperature would provide the bacteria clues of environmental location and dictate/modulate light photosensing in A. baumannii .