Separate photosensitizers mediate degradation of the 32-kDa photosystem II reaction center protein in the visible and UV spectral regions

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.17.6617· OSTI ID:5467823

Greenberg, B M; Gaba, V; Canaani, O; Malkin, S; Mattoo, A K; Edelman, M ^[1]

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1. Weizmann Institute of Science, Rehovot (Israel)

A component of the photosystem II reaction center, the 32-kDa protein, is rapidly turned over in the light. The mechanism of its light-dependent metabolism is largely unknown. We quantified the rate of 32-kDa protein degradation over a broad spectral range (UV, visible, and far red). The quantum yield for degradation was highest in the UVB (280-320 nm) region. Spectral evidence demonstrates two distinctly different photosensitizers for 32-kDa protein degradation. The data implicate the bulk photosynthetic pigments (primarily chlorophyll) in the visible and far red regions, and plastoquinone (in one or more of its redox states) in the UV region. A significant portion of 32-kDa protein degradation in sunlight is attributed to UVB irradiance.

• OSTI ID: 5467823
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 86:17; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CHLOROPHYLL
RADIOSENSITIVITY EFFECTS
PHOTOSYNTHETIC REACTION CENTERS
CHEMICAL RADIATION EFFECTS
PROTEINS
METABOLISM
QUINONES
DOSE-RESPONSE RELATIONSHIPS
MOLECULAR WEIGHT
PHOTOSYNTHESIS
PLANTS
ULTRAVIOLET RADIATION
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHEMISTRY
ELECTROMAGNETIC RADIATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
SYNTHESIS
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture