6LM0:
reference: A unique clade of light-driven proton-pumping rhodopsins evolved in the cyanobacterial lineage., Hasegawa M, Hosaka T, Kojima K, Nishimura Y, Nakajima Y, Kimura-Someya T, Shirouzu M, Sudo Y, Yoshizawa S, Sci Rep. 2020 Oct 7;10(1):16752. doi: 10.1038/s41598-020-73606-y. PMID: 33028840

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