title: Molecular identification and functional characterization of the first Nα-acetyltransferase in plastids by global acetylome profiling.
abstract: Protein N(α) -terminal acetylation represents one of the most abundant protein modifications of higher eukaryotes. In humans, six N(α) -acetyltransferases (Nats) are responsible for the acetylation of approximately 80% of the cytosolic proteins. N-terminal protein acetylation has not been evidenced in organelles of metazoans, but in higher plants is a widespread modification not only in the cytosol but also in the chloroplast. In this study, we identify and characterize the first organellar-localized Nat in eukaryotes. A primary sequence-based search in Arabidopsis thaliana revealed seven putatively plastid-localized Nats of which AT2G39000 (AtNAA70) showed the highest conservation of the acetyl-CoA binding pocket. The chloroplastic localization of AtNAA70 was demonstrated by transient expression of AtNAA70:YFP in Arabidopsis mesophyll protoplasts. Homology modeling uncovered a significant conservation of tertiary structural elements between human HsNAA50 and AtNAA70. The in vivo acetylation activity of AtNAA70 was demonstrated on a number of distinct protein N(α) -termini with a newly established global acetylome profiling test after expression of AtNAA70 in E. coli. AtNAA70 predominately acetylated proteins starting with M, A, S and T, providing an explanation for most protein N-termini acetylation events found in chloroplasts. Like HsNAA50, AtNAA70 displays N(ε) -acetyltransferase activity on three internal lysine residues. All MS data have been deposited in the ProteomeXchange with identifier PXD001947 (http://proteomecentral.proteomexchange.org/dataset/PXD001947).
authors.affiliation: Department of Plant Molecular Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany.
authors.forename: Trinh V
authors.initials: TV
authors.lastname: Dinh
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
authors.forename: Willy V
authors.initials: WV
authors.lastname: Bienvenut
authors.affiliation: Department of Plant Molecular Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany.|Hartmut Hoffmann-Berling International Graduate School, University of Heidelberg, Heidelberg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Linster
authors.affiliation: Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies gGbmH, Heidelberg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Feldman-Salit
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Jung
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Meinnel
authors.affiliation: Department of Plant Molecular Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hell
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
authors.forename: Carmela
authors.initials: C
authors.lastname: Giglione
authors.affiliation: Department of Plant Molecular Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Wirtz
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D063206:N-Terminal Acetyltransferases / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D018087:Plastids / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D040901:Proteomics; D053719:Tandem Mass Spectrometry
chemical_list: D063206:N-Terminal Acetyltransferases
keywords: Arabidopsis thaliana; AtNAA70; Chloroplast; Nα-acetyltransferase; Plant proteomics