Loss of phylloquinone in Chlamydomonas affects plastoquinone pool size and photosystem II synthesis

Article Article scientifique Article Loss of phylloquinone in Chlamydomonas affects plastoquinone pool size and photosystem II synthesis eng 2007 author Lefebvre-Legendre Linnka author Rappaport Fabrice author Finazzi Giovanni author Ceol Mauro 135536 author Grivet Chantal 22528 author Hopfgartner Gerard 0000-0002-9087-606X 31827 author Rochaix Jean-David 25289 13250-13263 10.1074/jbc.M610249200 17339322 0021-9258 http://www.jbc.org/cgi/reprint/282/18/13250 Phylloquinone functions as the electron transfer cofactor at the A(1) site of photosystem I. We have isolated and characterized a mutant of Chlamydomonas reinhardtii, menD1, that is deficient in MenD, which encodes 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase, an enzyme that catalyzes the first specific step of the phylloquinone biosynthetic pathway. The mutant is photosynthetically active but light-sensitive. Analysis of total pigments by mass spectrometry reveals that phylloquinone is absent in menD1, but plastoquinone levels are not affected. This is further confirmed by the rescue of menD1 by addition of phylloquinone to the growth medium. Analysis of electron transfer by absorption spectroscopy indicates that plastoquinone replaces phylloquinone in photosystem I and that electron transfer from A(1) to the iron-sulfur centers is slowed down at least 40-fold. Consistent with a replacement of phylloquinone by plastoquinone, the size of the free plastoquinone pool of menD1 is reduced by 20-30%. In contrast to cyanobacterial MenD-deficient mutants, photosystem I accumulates normally in menD1, whereas the level of photosystem II declines. This decrease is because of reduced synthesis of the photosystem II core subunits. The relationship between plastoquinone occupancy of the A(1) site in photosystem I and the reduced accumulation of photosystem II is discussed. Algal Proteins/genetics/metabolism Animals Chlamydomonas reinhardtii/enzymology/genetics Coenzymes/metabolism Electron Transport/genetics Mutation Oxo-Acid-Lyases/genetics/metabolism Photosystem I Protein Complex/genetics/metabolism Photosystem II Protein Complex/genetics/metabolism Plastoquinone/metabolism Vitamin K 1/metabolism Dewey 570 Dewey 580 Dewey 615 43 Département de biologie moléculaire 161 45 Département des sciences végétales 163 31 Section des sciences pharmaceutiques 17 false The Journal of biological chemistry 282 18 8867d2cb-f528-4bdd-bb3a-49ae616eb678 Article (Accepted version) Restricted article.pdf 2185682 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire Faculté des sciences / Section de biologie / Département des sciences végétales Faculté des sciences / Section des sciences pharmaceutiques

Title	Published in	Year	Views	Downloads

Regulation of chlorophyll synthesis in Chlamydomonas reinhardtii: the role of FLP and GUN4		2009	838	1,243
Loss of phylloquinone in Chlamydomonas affects plastoquinone pool size and photosystem II synthesis	The Journal of biological chemistry	2007	588	1

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