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The enzyme 3-deoxy-manno-octulosonate cytidylyltransferase (CMP-KDO synthetase; CKS) catalyzes the activation of 3-deoxy-D-manno-octulosonate (or 2-keto-3-deoxy-manno-octonic acid; KDO) by forming CMP-KDO. CKS is unique to Gram-negative bacteria and is an attractive target for the development of antibacterial agents. The crystal structure of CKS from Haemophilus influenzae in complex with the substrate KDO has been determined at 2.30 A resolution by combining single-wavelength anomalous diffraction and molecular-replacement methods. The two monomers in the asymmetric unit differ in the conformation of their C-terminal alpha-helix (Ala230-Asn254). The KDO bound to the active site exists as the beta-pyranose form in the (5)C(2) chair conformation. The structure of CKS from H. influenzae in complex with KDO will be useful in structure-based inhibitor design.

The enzyme nicotinic acid mononucleotide adenylyltransferase (NaMN AT; EC 2.7.7.18) is essential for the synthesis of nicotinamide adenine dinucleotide and is a potential target for antibiotics. It catalyzes the transfer of an adenyl group from ATP to nicotinic acid mononucleotide to form nicotinic acid adenine dinucleotide. NaMN AT from Pseudomonas aeruginosa was overexpressed in Escherichia coli and crystallized at 291 K using 100 mM bis-Tris propane pH 7.0, 700 mM trisodium citrate and 15%(v/v) glycerol. X-ray diffraction data have been collected to 1.70 A. The crystals are tetragonal, belonging to space group P4(1)22 (or P4(3)22), with unit-cell parameters a = b = 65.02, c = 109.80 A. The presence of one monomer in the asymmetric unit gives a reasonable V(M) of 2.15 A(3) Da(-1), with a solvent content of 42.7%.

The crystal structure of the core region of the alpha' subunit (alpha(c')) of soybean beta-conglycinin has been determined at 2.3 A resolution. alpha(c') was superimposed on the known crystal structure of the beta-conglycinin beta subunit with a small root-mean square deviation of 0.77 A, which is consistent with the high sequence identity of 75.5% between alpha(c') and the beta subunit. It is known that the thermal stability of the beta subunit is higher than that of the alpha' subunit and that their thermal stabilities are conferred by highly homologous core regions. Comparisons of the three-dimensional structures and primary sequences between alpha(c') and the beta subunit suggest that five factors account for this difference between subunits as regards the difference in thermal stability: (i) the total cavity volume is larger in alpha(c'), (ii) the cluster of charged residues at the intermonomer interface is smaller in alpha(c') and alpha(c') lacks the intermonomer salt bridge of the beta subunit, (iii) the solvent-accessible surface is more hydrophobic in alpha(c'), (iv) there are fewer proline residues in alpha(c') and (v) a loop region between helix 3 and strand J' in alpha(c') is more flexible owing to the insertion of five additional residues. Although more hydrogen bonds were found in alpha(c'), this difference should be more than compensated for by the combined contributions of these other factors.

Inorganic polyphosphate [poly(P)]/ATP-glucomannokinase from Arthrobacter sp. strain KM phosphorylates glucose and mannose, utilizing both ATP and poly(P) as phosphoryl donors. The enzyme was overexpressed in Escherichia coli, purified and crystallized by means of the hanging-drop vapour-diffusion method with ammonium sulfate as the precipitant. The crystals were orthorhombic and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 66.2, b = 83.7, c = 103.8 A. Assuming two molecules per asymmetric unit, V(sol) is 0.49. X-ray diffraction data to 2.83 A have been collected from a single crystal.

Alginate lyase depolymerizes alginate, a heteropolysaccharide consisting of alpha-L-guluronate and beta-D-mannuronate, through a beta-elimination reaction. A protein PA1167 with a molecular mass of 25 kDa produced by Pseudomonas aeruginosa is an alginate lyase classified into polysaccharide lyase family PL-7. The enzyme was crystallized at 293 K in a drop solution comprising 1.4 M sodium chloride, 0.1 M potassium sodium phosphate and 0.1 M 2-morpholinoethanesulfonate-sodium hydroxide pH 6.5 by means of the vapor-diffusion method. The crystals were monoclinic and belonged to space group P2(1), with unit-cell parameters a = 43.4, b = 70.3, c = 67.4 A, beta = 94.5 degrees. Diffraction data were collected to 2.0 A from a single crystal.

Unsaturated glucuronyl hydrolase from Bacillus sp. GL1 catalyzes the hydrolytic release of unsaturated glucuronic acids from oligosaccharides produced by the reactions of polysaccharide lyases such as gellan, xanthan, hyaluronate and chondroitin lyases. The enzyme was crystallized at 293 K from a droplet containing 56% MPD, 0.1 M NaCl, 0.1 M glycine-NaOH pH 8.2 and 0.1 M dithiothreitol using the vapour-diffusion method. The crystals were hexagonal and belonged to space group P6(1)22 or P6(5)22, with unit-cell parameters a = b = 102.8, c = 223.4 A. Diffraction data to 2.4 A were collected from a single crystal.