| X-RAY DIFFRACTION |
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277 |
The first crystals of GTA/GTB were grown as mercury derivatives (Patenaude, S.I., et al. 2002): 10 ul drops with 6-8 mg/ml protein, 70 mM N-(2-acetamido)-2-iminodiacetic acid (ADA) pH 7.5, 50 mM, sodium acetate pH 4.6, 40 mM NaCl, 5-8 mM MnCl2, 2.5% (v/v) 2-methyl-2,4-pentanediol (MPD), 5%(v/v) glycerol, 2%(w/v) PEG 4000, and 0.3-0.5 mM 3-chloromercuri-2-methoxypropylurea suspended over 1 ml of a resevoir solution: 50 mM ADA pH 7.5, 10 mM MnCl2, 100 mM ammonium sulfate, 5%(v/v) MPD, 10%(v/v) glycerol, and 8-10%(w/v) PEG 4000. Crystals were washed with artificial mother liquor ML-1 consisting of 10% polyethylene glycol (PEG) 4000, 30 mM N-(2-acetamido)-2-iminodiacetic acid (ADA) buffer pH 7.5, 30 mM sodium acetate buffer pH 4.6, 100 mM ammonium sulfate, 10 mM MnCl2 and 30% glycerol as the cryoprotectant. Crystals of GTA/GTB in complex with the A and B trisaccharides were obtained by soaking them in mother liquor ML-1 with 30% glycerol and 45-50 mM substrates for 2-5 days at 18 degrees Celsius |
