Kawasaki et al. identified three water-soluble astaxanthin binding proteins (AstaP) orthologs, AstaP-orange2, AstaP-pink1, and AstaP-pink2, in the eukaryotic microalga Scenedesmus sp. Oki-4N, grown under stress conditions. Their detailed characterisation showed that each AstaP ortholog had a specific absorption feature, but all were capable of quenching single oxygen. They envision that AstaP accumulation might have protective functions against photooxidative stress.