Herbicide binding in various mutants of the photosystem II D1 protein of Chlamydomonas reinhardtii

Abstract The orientation of acridones, xanthones, 1,4-benzo-and naphthoquinones within the photosystem II QB herbicide-binding niche was studied by means of mild trypsination and by estimation of pI50-values in Chlamydomonas reinhardtii D 1 mutants (Val219 > lie, Ala251 > Val, Phe255 > Tyr, Ser264 > Ala, Asn266 > Thr, and Leu275 > Phe). As judged from the R/S-values (ratios of I50 -values resistant versus susceptible type) close to 1 in all mutants, the acridones and xanthones do not have strong interactions with the parent amino acids. Contrary, the quinones exhibit extreme low R/S-values down to 0.003 (for 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone; DBMIB) in the Ser264 mutant. This extreme negative cross resistance or supersensitivity indicates that the quinones do not form a hydrogen bond to the serine hydroxyl group.

Download Full-text

Photosystem-II D1 protein mutants of Chlamydomonas reinhardtii in relation to metabolic rewiring and remodelling of H-bond network at QB site

Scientific Reports ◽

10.1038/s41598-018-33146-y ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 2

Author(s):

Amina Antonacci ◽

Maya D. Lambreva ◽

Andrea Margonelli ◽

Anatoly P. Sobolev ◽

Sandro Pastorelli ◽

...

Keyword(s):

Photosystem Ii ◽

Chlamydomonas Reinhardtii ◽

D1 Protein ◽

Protein Mutants ◽

Bond Network

Download Full-text

Photoinactivation of Photosystem II and Degradation of the D1 Protein are Reduced in a Cytochrome b6/f -Less Mutant of Chlamydomonas reinhardtii

Zeitschrift für Naturforschung C ◽

10.1515/znc-1990-0514 ◽

1990 ◽

Vol 45 (5) ◽

pp. 395-401 ◽

Cited By ~ 14

Author(s):

Susana Shochat ◽

Noam Adir ◽

Alma Gal ◽

Yorinao Inoue ◽

Laurence Mets ◽

...

Keyword(s):

Photosystem Ii ◽

Chlamydomonas Reinhardtii ◽

Reaction Center ◽

Electron Flow ◽

D1 Protein ◽

Charge Recombination ◽

Cyt B ◽

Variable Fluorescence ◽

Cytochrome B6 ◽

Mutant Cells

Abstract The effect of unoccupancy of the QB site by plastoquinone on the photoinactivation of reaction center II in a Cyt b6/f-less mutant of Chlamydomonas reinhardtii, B6, was investigated. In these cells the oxidation of plastoquinol generated by electron flow via RC II to plastoquinone and thus the turnover of PQH2/PQ via the QB site are drastically reduced. Reaction center II of the mutant cells was resistant to photoinactivation relative to the control cells as demonstrated by measurements of light-induced destabilization of S2-QB charge recombination, rise in in trinsic fluorescence and loss of variable fluorescence. These parameters relate to functions in volving the reaction center II D1 protein. The light-induced degradation of D1 in the mutant cells was also considerably reduced, with a t 1/2 value of 7 h as compared, under similar conditions, to about 1.5 h for the control cells. These results indicate that the photoinactivation of RC II and turnover of the D1 protein are related and require occupancy of the QB site by PQ and its light-driven reduction.

Download Full-text