Integration of Temperature and Blue‐Light Sensing in Acinetobacter baumannii Through the BlsA Sensor |
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| Authors: | Inés Abatedaga Lorena Valle Adrián E. Golic Gabriela L. Müller Matías Cabruja Faustino E. Morán Vieyra Paula C. Jaime María Alejandra Mussi Claudio D. Borsarelli |
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| Affiliation: | 1. Instituto de Bionanotecnología del NOA (INBIONATEC), Universidad Nacional de Santiago del Estero (UNSE), CONICET, Santiago del Estero, Argentina;2. Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI‐CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina;3. Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina |
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| 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. |
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