title: HMA6 and HMA8 are two chloroplast Cu+-ATPases with different enzymatic properties.
abstract: Copper (Cu) plays a key role in the photosynthetic process as cofactor of the plastocyanin (PC), an essential component of the chloroplast photosynthetic electron transfer chain. Encoded by the nuclear genome, PC is translocated in its apo-form into the chloroplast and the lumen of thylakoids where it is processed to its mature form and acquires Cu. In Arabidopsis, Cu delivery into the thylakoids involves two transporters of the PIB-1 ATPases family, heavy metal associated protein 6 (HMA6) located at the chloroplast envelope and HMA8 at the thylakoid membrane. To gain further insight into the way Cu is delivered to PC, we analysed the enzymatic properties of HMA8 and compared them with HMA6 ones using in vitro phosphorylation assays and phenotypic tests in yeast. These experiments reveal that HMA6 and HMA8 display different enzymatic properties: HMA8 has a higher apparent affinity for Cu(+) but a slower dephosphorylation kinetics than HMA6. Modelling experiments suggest that these differences could be explained by the electrostatic properties of the Cu(+) releasing cavities of the two transporters and/or by the different nature of their cognate Cu(+) acceptors (metallochaperone/PC).
authors.affiliation: CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Sautron
authors.affiliation: Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France.
authors.forename: Hubert
authors.initials: H
authors.lastname: Mayerhofer
authors.affiliation: CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Giustini
authors.affiliation: CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Danièle
authors.initials: D
authors.lastname: Pro
authors.affiliation: Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France *CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Crouzy
authors.affiliation: Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Ravaud
authors.affiliation: Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Pebay-Peyroula
authors.affiliation: CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Norbert
authors.initials: N
authors.lastname: Rolland
authors.affiliation: Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France *CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Catty
authors.affiliation: CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France Univ. Grenoble Alpes, F-38054 Grenoble, France CEA, DSV, iRTSV, F-38054 Grenoble, France INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France.
authors.forename: Daphné
authors.initials: D
authors.lastname: Seigneurin-Berny
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D025222:Chloroplast Proton-Translocating ATPases / Q000378:metabolism; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology; D017045:Lactococcus / Q000235:genetics; D062105:Molecular Docking Simulation; D010766:Phosphorylation; D010970:Plastocyanin / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics; D020524:Thylakoids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C000611728:HMA8 protein, Arabidopsis; D003300:Copper; D000255:Adenosine Triphosphate; D010970:Plastocyanin; D000251:Adenosine Triphosphatases; C000611727:HMA6 protein, Arabidopsis; D025222:Chloroplast Proton-Translocating ATPases
keywords: Arabidopsis; PIB-ATPase; chloroplast; copper; plant biochemistry; thylakoids; transporter