Fig. 1.

Schematic overview of the performed measurements for protein identification and quantification via stable ¹⁵N isotopic labeling. Whole cells grown in iron deficiency (¹⁴N (−Fe)) and iron sufficiency (¹⁵N (+Fe)) were harvested from photoheterotrophic conditions (PH) and photoautotrophic conditions (PA). Mixed samples of (¹⁵N (+Fe)) and (¹⁴N (−Fe)), which were separated via one-dimensional SDS-PAGE, were cut into 56 bands for PH and 54 and 59 bands for PA for two biological replicates, respectively. Isolated chloroplasts of a mix of (¹⁵N (+Fe)) and (¹⁴N (−Fe)) samples resulted in 54 and 56 bands for PH, 52 bands for PA and for isolated mitochondria in 62 bands for PH for two biological samples, respectively. The mix of samples from ¹⁴N PA and ¹⁵N PH in iron-sufficient conditions resulted in 56 bands for whole cells and 55 bands for isolated chloroplasts for two biological samples, respectively. For whole cells from iron-sufficient conditions also a label swap experiment was conducted (¹⁵N PA and ¹⁴N PH). Mitochondria could not be isolated from PA of (¹⁵N (+Fe)) and (¹⁴N (−Fe)). Therefore no measurements were carried out for isolated mitochondria from PA under these conditions as well as for the comparison of ¹⁴N PA to ¹⁵N PH.