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od 2020-09-20

Title: Crystallization and preliminary crystallographic studies of a new crystal form of Escherichia Coli L-asparaginase II (Ser58Ala mutant)

Source: Acta Crystallographica Section D-Biological Crystallography

Year : 2000

Abstract:

Periplasmic Escherichia coli L-asparaginase II with an Ser58Ala mutation in the active-site cavity has been crystallized in a new orthorhombic form (space group P2(1)2(1)2). Crystals of this polymorph suitable for X-ray diffraction have been obtained by vapour diffusion using two sets of conditions: (i) 1% agarose gel using MPD as precipitant (pH 4.8) and (ii) liquid droplets using PEG-MME 550 (pH 9.0). The crystals grown in agarose gel are characterized by unit-cell parameters a = 226.9, b = 128.4, c = 61.9 Angstrom and diffract to 2.3 Angstrom resolution. The asymmetric unit contains six protein molecules arranged into one pseudo-222-symmetric homotetramer and an active-site competent dimer from which another homotetramer is generated by crystallographic symmetry.

DOI: 10.1107/S0907444900000081   (Pobrane:  2020-10-23)