气候变化领域集成服务门户(CCPortal): Photosynthetic reaction center variants made via genetic code expansion show Tyr at M210 tunes the initial electron transfer mechanism

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DOI	10.1073/pnas.2116439118
	Photosynthetic reaction center variants made via genetic code expansion show Tyr at M210 tunes the initial electron transfer mechanism
	Weaver J.B.; Lin C.-Y.; Faries K.M.; Mathews I.I.; Russi S.; Holten D.; Kirmaier C.; Boxer S.G.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:51
英文摘要	Photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides were engineered to vary the electronic properties of a key tyrosine (M210) close to an essential electron transfer component via its replacement with site-specific, genetically encoded noncanonical amino acid tyrosine analogs. High fidelity of noncanonical amino acid incorporation was verified with mass spectrometry and X-ray crystallography and demonstrated that RC variants exhibit no significant structural alterations relative to wild type (WT). Ultrafast transient absorption spectroscopy indicates the excited primary electron donor, P∗, decays via a ~4-ps and a ~20-ps population to produce the charge-separated state P+HA-in all variants. Global analysis indicates that in the ~4-ps population, P+HA-forms through a two-step process, P∗ → P+BA-→ P+HA-, while in the ~20-ps population, it forms via a one-step P∗→ P+HA-superexchange mechanism. The percentage of the P∗population that decays via the superexchange route varies from ~25 to ~45% among variants, while inWT, this percentage is ~15%. Increases in the P∗ population that decays via superexchange correlate with increases in the free energy of the P+BA-intermediate caused by a given M210 tyrosine analog. This was experimentally estimated through resonance Stark spectroscopy, redox titrations, and nearinfrared absorption measurements. As the most energetically perturbative variant, 3-nitrotyrosine at M210 creates an ~110-meV increase in the free energy of P+BA-along with a dramatic diminution of the 1,030-nm transient absorption band indicative ofP+BA-formation. Collectively, this work indicates the tyrosine at M210 tunes the mechanism of primary electron transfer in the RC. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Noncanonical amino acid; Reaction center; Stark spectroscopy; Superexchange; Ultrafast transient absorption spectroscopy
语种	英语
scopus关键词	bacterial protein; amino acid sequence; electron transport; gene expression regulation; genetic variation; genetics; metabolism; photosynthesis; physiology; protein conformation; Rhodobacter sphaeroides; Amino Acid Sequence; Bacterial Proteins; Electron Transport; Gene Expression Regulation, Bacterial; Genetic Variation; Photosynthetic Reaction Center Complex Proteins; Protein Conformation; Rhodobacter sphaeroides
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/250919
作者单位	Department of Chemistry, Stanford University, Stanford, CA 94305, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130-4889, United States; Structural Molecular Biology, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States
推荐引用方式 GB/T 7714	Weaver J.B.,Lin C.-Y.,Faries K.M.,et al. Photosynthetic reaction center variants made via genetic code expansion show Tyr at M210 tunes the initial electron transfer mechanism[J],2021,118(51).
APA	Weaver J.B..,Lin C.-Y..,Faries K.M..,Mathews I.I..,Russi S..,...&Boxer S.G..(2021).Photosynthetic reaction center variants made via genetic code expansion show Tyr at M210 tunes the initial electron transfer mechanism.Proceedings of the National Academy of Sciences of the United States of America,118(51).
MLA	Weaver J.B.,et al."Photosynthetic reaction center variants made via genetic code expansion show Tyr at M210 tunes the initial electron transfer mechanism".Proceedings of the National Academy of Sciences of the United States of America 118.51(2021).