Apocrustacyanin A1 from the lobster carotenoprotein alpha-crustacyanin: crystallization and initial X-ray analysis involving softer X-rays

The A1 subunit of the carotenoprotein alpha-crustacyanin, isolated from lob ster carapace, has been crystallized using the vapour-diffusion method. The crystals, grown in solutions of ammonium sulfate containing methylpentaned iol (MPD), diffracted to 2.0 Angstrom. The crystals are stable to radiation . The space group of the crystals is P2(1)2(1)2(1). The unit-cell parameter s are a = 41.9, b = 80.7, c = 110.8 Angstrom. 'Standard structure determina tion' has been unsuccessful within this crustacyanin family. Instead, an ap proach based on the S atoms is being undertaken involving softer X-rays at the SRS, Daresbury.