title: Mechanism of colour discrimination by a bacterial sensory rhodopsin.
abstract: A photosensitive protein resembling the visual pigments of invertebrates enables phototactic archaebacteria to distinguish colour. This protein exists in two spectrally-distinct forms, one of which is a transient photoproduct of the other and each of which undergoes photochemical reactions controlling the cell's swimming behaviour. Activation of a single pigment molecule in the cell is sufficient to signal the flagellar motor. This signal-transduction mechanism makes evident a colour-sensing capability inherent in the retinal/protein chromophore.
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology; D001436:Bacteriorhodopsins / Q000502:physiology*; D002338:Carotenoids / Q000502:physiology*; D003118:Color Perception; D006217:Halobacterium / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D009068:Movement; D010777:Photochemistry; D013057:Spectrum Analysis
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D002338:Carotenoids; D001436:Bacteriorhodopsins