Chlorophyll to zeaxanthin energy transfer in nonphotochemical quenching: An exciton annihilation- free transient absorption study

• 成果类型: Article
• 署名作者: Lee, Tsung- Yen; Lam, Lam; Patel-Tupper, Dhruv; Roy, Partha Pratim; Ma, Sophia A.; Lam, Henry E.; DeMott, Aviva Lucas-; Karavolias, Nicholas G.; Iwai, Masakazu; Niyogi, Krishna K.; Fleming, Graham R.
• 署名单位: University of California System; University of California Berkeley; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of California System; University of California Berkeley; University of California System; University of California Berkeley; University of California System; University of California Berkeley; Howard Hughes Medical Institute; University of California System; University of California Berkeley
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14625
• DOI: 10.1073/pnas.2411620121
• 发表日期: 2024-10-15
• 关键词: light-harvesting complex; charge-transfer; xanthophyll cycle; cation formation; in-vivo; lutein; antenna; violaxanthin; DISSIPATION; mechanism

摘要

Zeaxanthin (Zea) is a key component in the energy- dependent, rapidly reversible, non- photochemical quenching process (qE) that regulates photosynthetic light harvesting. Previous transient absorption (TA) studies suggested that Zea can participate in direct quenching via chlorophyll (Chl) to Zea energy transfer. However, the contamination of intrinsic exciton-exciton annihilation (EEA) makes the assignment of TA signal ambiguous. In this study, we present EEA-free TA data using Nicotiana benthamiana thylakoid membranes, including the wild type and three NPQ mutants ( npq1 , npq4, and lut2) generated by CRISPR/Cas9 mutagenesis. The results show a strong correlation between excitation energy transfer from excited Chl Q(y) to Zea S-1 and the xanthophyll cycle during qE activation. Notably, a Lut S(1 )signal is absent in the npq1 thylakoids which lack zeaxanthin. Additionally, the fifth- order response analysis shows a reduction in the exciton diffusion length (L-D) from 62 +/- 6 nm to 43 +/- 3 nm under high light illumination, consistent with the reduced range of exciton motion being a key aspect of plants' response to excess light.