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Triosephosphate isomerase from methicillin-resistant Staphylococcus aureus (MRSA252) was cloned in pQE30 vector, overexpressed in Escherichia coli M15 (pREP4) cells and purified to homogeneity. The protein was crystallized from 1.6 M trisodium citrate dihydrate pH 6.5 using the hanging-drop vapour-diffusion method. The crystals belonged to space group P4(3)2(1)2, with unit-cell parameters a = b = 79.15, c = 174.27 A. X-ray diffraction data were collected and processed to a maximum resolution of 1.9 A. The presence of two molecules in the asymmetric unit gave a Matthews coefficient (V(M)) of 2.64 A(3) Da(-1), with a solvent content of 53.63%.

Recombinant triosephosphate isomerase (TIM) from a hyperthermophilic Archaeon, Pyrococcus woesei, has been crystallized. Three crystal forms have been obtained: monoclinic, orthorhombic and hexagonal. The monoclinic crystals belong to space group P21 with cell dimensions a = 79.1, b = 89.2, c = 145.4 A and beta = 92.8 degrees, and diffract to at least 2.6 A. The orthorhombic crystals belong to space group P21212 with a = 89.4, b = 155.9, c = 79.5 A, and diffract to 2.9 A. Diffraction from the hexagonal form showed extensive disorder. The monoclinic form contains two tetramers in the asymmetric unit, which are in the same orientation but related by a pseudo-centering. The orthorhombic form contains one tetramer in the asymmetric unit which is in approximately the same orientation as in the monoclinic form. Knowledge of the structure of this hyperthermostable TIM, which is tetrameric in contrast to dimeric forms previously observed, will add to our understanding of protein thermostability.

This paper presents the results of a survey of Japanese for electrophoretic variants of CA I, CA II, LDH, MDH, TPI, NP, HB A and A2, the number of determinations per system ranging from 738 to 4029. Four similar variants of CA I (designed CA IHIR1), one of LDH (designated LDHNGS1), one of MDH (designated MDHS 7HIR1), two of HB A (one a reascertainment of HB Hijiyama, the other not characterized), and one characterized by the absence of HB A2 (delta-thalassaemia) were observed and are described. The CA IHIR1, LDHNAG1 and MDHS 2HIR1 variants have not been previously observed in Japan. No electrophoretic variants were found in the TPI and NP systems.