2:55 PM - 3:15 PM
[BBG01-04] Use light? Defending against light? Insights into Microbial Rhodopsin and Intracellular Pigments
★Invited Papers
Keywords:Bacterial pigments, Rhodopsin, Microbial ecology
Light derived from the sun is the fundamental energy source for driving almost all biological processes. The system capable of converting sunlight into chemical energy is generally "photosynthesis.” However, microbial rhodopsin is also a photoreceptor that converts light into energy available to living organisms. Microbial rhodopsins are seven-transmembrane photoreceptor proteins containing retinal, a derivative of β-carotene, as a chromophore. Light absorption by the retinal induces structural changes in microbial rhodopsin, activating its various functions. Although several different functions are known for microbial rhodopsins, the light-driven H+ pump, which transports H+ from inside to outside the cell upon light reception, is the most prevalent rhodopsin in the global environment. Bacteria leverage sunlight for various physiological processes by converting light energy into membrane potential through rhodopsin-mediated ion transport. Recent studies have highlighted the dominance of rhodopsin-possessing bacteria in the surface layers of diverse aquatic environments, including oceans, drawing renewed attention to the relationship between bacteria and light.
Retinal binding is crucial for rhodopsin to respond to light stimuli. Consequently, most rhodopsin-possessing bacteria have conserved genes for carotenoid biosynthesis and retinal biosynthesis from β-carotene in their genomes. The representative pigments produced by bacteria include carotenoids and aryl polyenes, which have traditionally been studied for their roles as antioxidants. However, the discovery of microbial rhodopsins across various taxa suggests that bacterial pigments such as carotenoids not only function as antioxidants but also play a role in rhodopsin-mediated light energy reception, highlighting the multifaceted roles of intracellular pigments.
In this presentation, I will discuss how the varied intracellular pigments produced by bacteria contribute to rhodopsin-mediated light utilization and intracellular physiology.
Retinal binding is crucial for rhodopsin to respond to light stimuli. Consequently, most rhodopsin-possessing bacteria have conserved genes for carotenoid biosynthesis and retinal biosynthesis from β-carotene in their genomes. The representative pigments produced by bacteria include carotenoids and aryl polyenes, which have traditionally been studied for their roles as antioxidants. However, the discovery of microbial rhodopsins across various taxa suggests that bacterial pigments such as carotenoids not only function as antioxidants but also play a role in rhodopsin-mediated light energy reception, highlighting the multifaceted roles of intracellular pigments.
In this presentation, I will discuss how the varied intracellular pigments produced by bacteria contribute to rhodopsin-mediated light utilization and intracellular physiology.