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Directed mutagenesis indicates that the donor to P sup + sub 680 in photosystem II is tyrosine-161 of the D1 polypeptide

Journal Article · · Biochemistry; (USA)
DOI:https://doi.org/10.1021/bi00426a001· OSTI ID:5565116
; ; ; ;  [1]
  1. Michigan State Univ., East Lansing (USA)
+ Show Author Affiliations
Photosystem II contains two redox-active tyrosines. One of these, Y{sub Z}, reduces the reaction center chlorophyll, P680, and transfers the oxidizing equivalent to the oxygen-evolving complex. The second, Y{sub D}, has a long-lived free radical state of unknown function. The authors, recently established that Y{sub D} is Tyr-160 of the D2 polypeptide by site-directed mutagenesis of a psbD gene in the unicellular cyanobacterium Synechocystis 6803. Y{sub Z} is most likely the symmetry-related Tyr-161 of the D1 polypeptide. To test this hypothesis, they have changed Tyr-161 to phenylalanine by site-directed mutagenesis of a psb A gene in Synechocystis. The resulting mutant assembles PSII, as judged by its ability to produce the stable Y{sup +}{sub D} radical, but is unable to grow photosynthetically and exhibits altered fluorescence properties. The nature of the fluorescence change indicates that forward electron transfer to P{sup +}{sub 680} is disrupted in the mutant. These results provide strong support for our identification of Tyr-161 in the D1 polypeptide with Y{sub Z}.
OSTI ID:
5565116
Journal Information:
Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 27:26; ISSN 0006-2960; ISSN BICHA
Country of Publication:
United States
Language:
English

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Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHLOROPHYLL
DAYS LIVING RADIOISOTOPES
DNA
ELECTRON TRANSFER
GENES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYBRIDIZATION
HYDROXY ACIDS
ISOTOPES
LIGHT NUCLEI
MUTAGENESIS
MUTANTS
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDES
PHENYLALANINE
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOTOSYNTHETIC REACTION CENTERS
PHYTOCHROMES
PIGMENTS
POLYPEPTIDES
PORPHYRINS
PROTEINS
RADIOISOTOPES
TYROSINE