Popeye strikes again: The deep proteome of spinach leaves

The cytoplasmic proteome of spinach leaves (Spinacia oleracea L) has been investigated with the help of commercially available (ProteoMiner) combinatorial peptide ligand libraries and with home-made ligand beads as prepared in our laboratory. The protein capture had been performed at three pH values (4.0, 7.0 and 9.3) and elution performed in 4% boiling SDS, 20 mM DTT. The total number of unique gene products identified amounts to 322 proteins, of which 114 are in common with the control, untreated sample, 18 are present only in the control and 190 represent the new species detected with the help of all combined eluates and likely represent low-abundance species. This is the first in depth exploration of the spinach cytoplasmic proteome and might enable further studies on interaction, regulation and expression of proteins biological processes in combination or not with transcriptomics data.

Graphical abstractPopeye kept gulping down large amounts of spinaches to become the first iron-man of America, not knowing that spinach leaves would comprise not less than 322 proteins as listed therein.Figure optionsDownload full-size imageDownload high-quality image (106 K)Download as PowerPoint slideResearch highlights► A grand total of 322 cytoplasmic proteins detected in spinach leaves. ► Rubisco levels strongly cut down by ProteoMiner treatment. ► Peptide libraries allow detection of 190 low-abundance species over the control. ► Protein capture by ligand libraries enhanced at different pH values.