| 1. |
- Larsson, Gunilla, et al.
(författare)
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Crystal structure of the Escherichia coli dUTPase in complex with a substrate analogue (dUDP)
- 1996
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Ingår i: Nature Structural & Molecular Biology. - : Springer Science and Business Media LLC. - 1545-9985 .- 1545-9993. ; 3:6, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- We have determined the structure of the homotrimeric dUTPase from Escherichia coli, complexed with an inhibitor and substrate analogue, dUDP. Three molecules of dUDP are found symmetrically bound per trimer, each in a shallow cleft between adjacent subunits, interacting with evolutionary conserved residues. The interactions of the uracil ring and the deoxypentose with the protein are consistent with the high specificity of the enzyme with respect to these groups. The positions of the two phosphate groups and adjacent water molecules are discussed in relation to the mechanism and kinetics of catalysis. The role that dUTPase plays in DNA metabolism makes the enzyme a potential target for chemotherapeutic drugs: the results presented here will aid in the design and development of inhibitory compounds.
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| 2. |
- Larsson, G, et al.
(författare)
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Crystallization and preliminary X-ray analysis of human dUTPase
- 1996
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Ingår i: Acta Crystallographica. Section D: Biological Crystallography. - 1399-0047. ; D52:5, s. 1039-1040
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Tidskriftsartikel (refereegranskat)abstract
- Human dUTPase, expressed in Escherichia coli, has been crystallized. Single crystals were obtained by the vapour-diffusion technique using 2-propanol and PEG 4000 as precipitants. The enzyme was co-crystallized with the substrate dUTP and a metal chelator EDTA to prevent hydrolysis of the substrate. The crystals belong to the orthorombic space group P212121 with cell dimensions a = 67.51, b = 68.26 and c = 91.00 Å. The crystallographic asymmetric unit contains one trimer of identical subunits.
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| 3. |
- Larsson, Per-Olof, et al.
(författare)
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Combustion of CO and toluene; Characterisation of copper oxide supported on titania and activity comparisons with supported cobalt, iron, and manganese oxide
- 1996
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Ingår i: Journal of Catalysis. - : Elsevier BV. - 1090-2694 .- 0021-9517. ; 163:2, s. 279-293
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Tidskriftsartikel (refereegranskat)abstract
- Titania-supported copper oxide catalysts have been prepared with loadings in the range from 1/3 to 5 theoretical layers and have been tested for the combustion of CO and toluene. Characterisation with XRD, electron microscopy, EDX, TPR, Raman, and XPS gives details about the structure of copper oxide on titania. The results show that dispersed CuOx is formed up to a loading of about one theoretical layer. TPR indicates the formation of two types of dispersed species, which possibly are isolated and polymeric, respectively. XPS data show that the dispersed copper is Cu2+. Th, dispersed species have high catalytic activity for combustion. At higher copper oxide loading, bulk CuO is formed, contributing little to the activity. Comparison of three titania supports with differing surface area and pore size distribution shows that the most favorable is a support with a surface area of about 38 m(2)/g and mesopores in the range 100-800 Angstrom. The longevity of the catalysts was tested in the waste gas from a formaldehyde plant. Deactivation was observed after being on stream for 57 days, and the deactivation is due to sintering of both the support and the copper oxide. Copper oxide on titania is shown to be more active than cobalt, manganese, and iron oxide on the same support. (C) 1996 Academic Press, Inc.
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