气候变化领域集成服务门户(CCPortal): Crystal structure of a far-red–sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism

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DOI	10.1073/pnas.2025094118
	Crystal structure of a far-red–sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism
	Bandara S.; Rockwell N.C.; Zeng X.; Ren Z.; Wang C.; Shin H.; Martin S.S.; Moreno M.V.; Clark Lagarias J.; Yang X.
发表日期	2021
ISSN	00278424
卷号	118 期号:12
英文摘要	Cyanobacteriochromes (CBCRs) are small, linear tetrapyrrole (bilin)binding photoreceptors in the phytochrome superfamily that regulate diverse light-mediated adaptive processes in cyanobacteria. More spectrally diverse than canonical red/far-red–sensing phytochromes, CBCRs were thought to be restricted to sensing visible and near UV light until recently when several subfamilies with far-red–sensing representatives (frCBCRs) were discovered. Two of these frCBCRs subfamilies have been shown to incorporate bilin precursors with larger pi-conjugated chromophores, while the third frCBCR subfamily uses the same phycocyanobilin precursor found in the bulk of the known CBCRs. To elucidate the molecular basis of far-red light perception by this third frCBCR subfamily, we determined the crystal structure of the far-red–absorbing dark state of one such frCBCR Anacy_2551g3 from Anabaena cylindrica PCC 7122 which exhibits a reversible far-red/orange photocycle. Determined by room temperature serial crystallography and cryocrystallography, the refined 2.7-Å structure reveals an unusual all-Z,syn configuration of the phycocyanobilin (PCB) chromophore that is considerably less extended than those of previously characterized red-light sensors in the phytochrome superfamily. Based on structural and spectroscopic comparisons with other bilin-binding proteins together with site-directed mutagenesis data, our studies reveal protein–chromophore interactions that are critical for the atypical bathochromic shift. Based on these analyses, we propose that far-red absorption in Anacy_ 2551g3 is the result of the additive effect of two distinct red-shift mechanisms involving cationic bilin lactim tautomers stabilized by a constrained all-Z,syn conformation and specific interactions with a highly conserved anionic residue. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Bilin-based photoreceptor \| optogenetics \| serial crystallography \| far-red-light sensing \| bilin tautomers
语种	英语
scopus关键词	Anabaena cylindrica; Article; bilin conformation; chromatophore; conformation; controlled study; cryocrystallography; crystal structure; crystallography; cyanobacteriochrome; molecular interaction; nonhuman; photoreceptor; priority journal; room temperature; site directed mutagenesis; ultraviolet radiation
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180132
作者单位	Department of Chemistry, University of Illinois, Chicago, IL 60607, United States; Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, United States; Department of Ophthalmology and Vision Sciences, University of Illinois, Chicago, IL 60607, United States
推荐引用方式 GB/T 7714	Bandara S.,Rockwell N.C.,Zeng X.,等. Crystal structure of a far-red–sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism[J],2021,118(12).
APA	Bandara S..,Rockwell N.C..,Zeng X..,Ren Z..,Wang C..,...&Yang X..(2021).Crystal structure of a far-red–sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism.Proceedings of the National Academy of Sciences of the United States of America,118(12).
MLA	Bandara S.,et al."Crystal structure of a far-red–sensing cyanobacteriochrome reveals an atypical bilin conformation and spectral tuning mechanism".Proceedings of the National Academy of Sciences of the United States of America 118.12(2021).