Updated project metadata. We surveyed the heterogeneity of the mitochondrial proteome and its function during a typical night and day cycle in Arabidopsis shoots. This used a staged, quantitative analysis of the proteome across 10 time points covering 24 h of the life of 3-week-old Arabidopsis shoots grown under 12-h dark and 12-h light conditions. Results were queried against an in-house Arabidopsis database comprising ATH1.pep (release 7) from The Arabidopsis Information Resource and the Arabidopsis mitochondrial and plastid protein sets (the combined database contained a total of 30,700 protein sequences with 12,656,682 residues) using the Mascot search engine version 2.2 and utilizing error tolerances of +-1.2 Da for MS and +-0.6 Da for MS/MS, 'enzyme' set to trypsin, 'maximum missed cleavages' set to 1, variable modifications of oxidation (Met) and carbamidomethyl (Cys), instrument set to ESI-TRAP, and peptide charge set at 2+ and 3+. ATH1.pep is a non-redundant database with systematically named protein sequences based on Arabidopsis genome sequencing and annotation. PRIDE XML files with accession numbers 10471–10525 and without peptide/protein identifications have already been made public.