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Titolo:
THE CYANOBACTERIUM SYNECHOCOCCUS RESISTS UV-B BY EXCHANGING PHOTOSYSTEM-II REACTION-CENTER D1 PROTEINS
Autore:
CAMPBELL D; ERIKSSON MJ; OQUIST G; GUSTAFSSON P; CLARKE AK;
Indirizzi:
UMEA UNIV,DEPT PLANT PHYSIOL S-90187 UMEA SWEDEN UMEA UNIV,DEPT PLANT PHYSIOL S-90187 UMEA SWEDEN
Titolo Testata:
Proceedings of the National Academy of Sciences of the United Statesof America
fascicolo: 1, volume: 95, anno: 1998,
pagine: 364 - 369
SICI:
0027-8424(1998)95:1<364:TCSRUB>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
SP STRAIN PCC-7942; HIGH LIGHT-INTENSITY; 2 FORMS; GENE FAMILY; ULTRAVIOLET-RADIATION; PSBA GENES; EXPRESSION; PHOTOINHIBITION; PHOTOSYNTHESIS; INACTIVATION;
Keywords:
PHOTOSYNTHESIS; PHYCOBILIPROTEIN; PSBA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
D. Campbell et al., "THE CYANOBACTERIUM SYNECHOCOCCUS RESISTS UV-B BY EXCHANGING PHOTOSYSTEM-II REACTION-CENTER D1 PROTEINS", Proceedings of the National Academy of Sciences of the United Statesof America, 95(1), 1998, pp. 364-369

Abstract

Current ambient UV-B levels can significantly depress productivity inaquatic habitats, largely because UV-B inhibits several steps of photosynthesis, including the photooxidation of water catalyzed by photosystem II, We show that upon UV-B exposure the cyanobacterium Synechococcus sp, PCC 7942 rapidly changes the expression of a family of three psbA genes encoding photosystem II D1 proteins, In wild-type cells the psbAI gene is expressed constitutively, but strong accumulations of psbAII and psbAIII transcripts are induced within 15 min of moderate UV-B exposure (0.4 W/m(2)), This transcriptional response causes an exchange of two distinct photosystem II D1 proteins, D1:1 is encoded by psbAI, but on UV-B exposure, it is largely replaced by the alternate D1:2form, encoded by both psbAII and psbAIII, The total content of D1 andother photosystem II reaction center protein, D2, remained unchanged throughout the UV exposure, as did the content and composition of the phycobilisome, Wild-type cells suffered only slight transient inhibition of photosystem II function under UV-B exposure, In marked contrast,under the same UV-B treatment, a mutant strain expressing only psbAI suffered severe (40%) and sustained inhibition of photosystem II function, Another mutant strain with constitutive expression of psbAII and psbAIII was almost completely resistant to the UV-B treatment, showingno inhibition of photosystem II function and only a slight drop in electron transport, In Synechococcus the rapid exchange of alternate D1 forms, therefore, accounts for much of the cellular resistance to UV-Binhibition of photosystem II activity and photosynthetic electron transport, This molecular plasticity may be an important element in community-level responses to UV-B, where susceptibility to UV-B inhibition of photosynthesis changes diurnally.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/10/20 alle ore 03:35:10