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Title
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X-ray studies of recombinant anti-testosterone Fab fragments: the use of PEG 3350 in crystallization.
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Authors
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J.Valjakka,
A.Hemminki,
T.Teerinen,
K.Takkinen,
J.Rouvinen.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2000,
56,
218-221.
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PubMed id
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Abstract
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Recombinant anti-testosterone wild-type Fab fragment and mutant Fab fragments
with high binding selectivity developed by protein engineering have been
crystallized with and without ligands. Crystals of these Fab fragments were
obtained by the vapour-diffusion technique at room temperature using solutions
of PEG 3350 with various biological buffers and with a wide pH range. So far,
five data sets have been collected from crystals of three Fab-antigen complexes
and from two uncomplexed Fab fragments, with resolutions ranging from 2.10 to
3.1 A. Crystallization conditions for Fab fragments were found by using
modifications of the low ionic strength PEG 3350 series. Suitable concentrations
of PEG 400, MPD and glycerol solutions for use as cryoprotectants in PEG 3350
solutions have been determined. One useful observation was that PEG 3350 is able
to work alone as a cryoprotectant. The screening protocol used requires a
smaller amount of protein material to achieve auspicious pre-crystals than
previously. Results support the claim that PEG 3350 is more suitable for the
crystallization of Fab fragments than higher molecular weight PEGs.
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