PPL1 (PSBP-LIKE PROTEIN 1); calcium ion binding. Identical to PsbP-related thylakoid lumenal protein 2, chloroplast precursor [Arabidopsis Thaliana] (GB:P82538); similar to PPL2 (PSBP-LIKE PROTEIN 2), calcium ion binding [Arabidopsis thaliana] (TAIR:AT2G39470.2); similar to PPL2 (PSBP-LIKE PROTEIN 2), calcium ion binding [Arabidopsis thaliana] (TAIR:AT2G39470.1); similar to unnamed protein product [Vitis vinifera] (GB:CAO69262.1); contains InterPro domain Mog1/PsbP/DUF1795, alpha/beta/alpha sandwich (InterPro:IPR016124); contains InterPro domain Mog1/PsbP, alpha/beta/alpha sandwich (InterPro:IPR016123); contains InterPro domain Photosystem II