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ATP-binding cassette (ABC) transporters, also known as traffic ATPases, form a large family of integral membrane proteins responsible for the translocation of a variety of chemically diverse substrates across the lipid bilayers of cellular membranes of both prokaryotes and eukaryotes by the hydrolysis of ATP. The ATP-binding subunit of an ABC transporter from Geobacillus kaustophilus, a homodimeric enzyme, was overexpressed in Escherichia coli and purified. Crystals were obtained using the microbatch-under-oil method at 291 K. X-ray diffraction data to 1.6 Å resolution were collected on SPring-8 beamline BL26B1. The crystals belonged to the orthorhombic space group I222, with unit-cell parameters a=54.94, b=78.63, c=112.96 Å. Assuming the presence of a dimer in the asymmetric unit gave a crystal volume per protein weight (VM) of 2.32 Å3 Da(-1) and a solvent content of 47%; this was consistent with the results of a dynamic light-scattering experiment, which showed a dimeric state of the protein in solution. Molecular-replacement trials using the crystal structure of HisP from the Salmonella typhimurium ATP-binding subunit of an ABC transporter as a search model did not provide a satisfactory solution, indicating that the two ATP-binding subunits of ABC transporters have substantially different structures.

Enolase is a glycolytic enzyme that catalyzes the interconversion of phosphoenolpyruvate and 2-phosphoglycerate. In order to gain insight into the biological significance of the oligomeric state of this enzyme, the putative enolase MJ0232 from the hyperthermophilic archaeon Methanococcus jannaschii was cloned, overexpressed and purified. Crystals were obtained by the oil-microbatch method at 291 K using PEG 4000 as a precipitant. A native data set was collected to 1.85 A resolution. The crystal belonged to the tetragonal space group I4, with unit-cell parameters a = 148.8, c = 91.2 A. An initial model was obtained by molecular replacement, which revealed an octameric subunit association (a tetramer of dimers). This result is consistent with that from a dynamic light-scattering experiment, suggesting biological relevance of the octameric state of MJ0232 in solution.

The structure of human brain CutA1 (HsCutA1) has been determined using diffraction data to 2.05 A resolution. HsCutA1 has been implicated in the anchoring of acetylcholinesterase in neuronal cell membranes, while its bacterial homologue Escherichia coli CutA1 is involved in copper tolerance. Additionally, the structure of HsCutA1 bears similarity to that of the signal transduction protein PII, which is involved in regulation of nitrogen metabolism. Although several crystal structures of CutA1 from various sources with different rotation angles and degrees of interaction between trimer interfaces have been reported, the specific functional role of CutA1 is still unclear. In this study, the X-ray structure of HsCutA1 was determined in space group P2(1)2(1)2(1), with unit-cell parameters a = 68.69, b = 88.84, c = 125.33 A and six molecules per asymmetric unit. HsCutA1 is a trimeric molecule with intertwined antiparallel beta-strands; each subunit has a molecular weight of 14.6 kDa and contains 135 amino-acid residues. In order to obtain clues to the possible function of HsCutA1, its crystal structure was compared with those of other CutA1 and PII proteins.

The beta-ketoacyl-(acyl carrier protein) synthases (beta-keto-ACP synthases; KAS) catalyse the addition of two-carbon units to the growing acyl chain during the elongation phase of fatty-acid synthesis. As key regulators of bacterial fatty-acid synthesis, they are promising targets for the development of new antibacterial agents. The crystal structure of 3-oxoacyl-ACP synthase II from Thermus thermophilus HB8 (TtKAS II) has been solved by molecular replacement and refined at 2.0 A resolution. The crystal is orthorhombic, space group P2(1)2(1)2, with unit-cell parameters a = 72.07, b = 185.57, c = 62.52 A, and contains one homodimer in the asymmetric unit. The subunits adopt the well known alpha-beta-alpha-beta-alpha thiolase fold that is common to ACP synthases. The structural and sequence similarities of TtKAS II to KAS I and KAS II enzymes of known structure from other sources support the hypothesis of comparable enzymatic activity. The dimeric state of TtKAS II is important to create each fatty-acid-binding pocket. Closer examination of KAS structures reveals that compared with other KAS structures in the apo form, the active site of TtKAS II is more accessible because of the ;open' conformation of the Phe396 side chain.

Rabbit L-gulonate 3-dehydrogenase was crystallized using the oil-microbatch method at 295 K. X-ray diffraction data were collected to 1.70 A resolution from a crystal at 100 K using synchrotron radiation. The crystal belongs to the C-centred monoclinic space group C2, with unit-cell parameters a = 71.81, b = 69.08, c = 65.64 A, beta = 102.7 degrees. Assuming the presence of a monomeric protomer in the asymmetric unit gives a V(M) value of 2.21 A(3) Da(-1) and a solvent content of 44.4%. A cocrystal with NADH, which was isomorphous to the apo form, was also prepared and diffraction data were collected to 1.85 A resolution using Cu Kalpha radiation at 100 K.

Fumarylacetoacetase catalyzes the final step of tyrosine and phenylalanine catabolism. A recombinant form of the fumarylacetoacetase family member TTHA0809 from Thermus thermophilus HB8 has been crystallized by the oil-microbatch method using sodium chloride as a precipitating agent. The crystals belong to the monoclinic space group P2(1), with unit-cell parameters a = 93.3, b = 73.4, c = 122.6 A, beta = 111.8 degrees. The crystals are most likely to contain two dimers in the asymmetric unit, with a V(M) value of 3.32 A3 Da(-1). Diffraction data were collected at 2.2 A resolution using synchrotron radiation at beamline BL26B1 of SPring-8, Japan.

A putative UDP-N-acetyl-D-mannosamine dehydrogenase from Pyrococcus horikoshii OT3, an essential enzyme for polysaccharide biosynthesis, has been overexpressed in Escherichia coli and purified. Crystals were obtained using the oil-microbatch method at 291 K. A native data set extending to 1.8 A resolution has been collected and processed in space group P2(1). Assuming the presence of a dimer in the asymmetric unit, the V(M) value is calculated to be 2.3 A3 Da(-1), which is consistent with the result of a dynamic light-scattering experiment that shows a dimeric state of the protein in solution.

Biotin protein ligase (BPL) catalyses the biotinylation of the biotin carboxyl carrier protein (BCCP) subunit of acetyl-CoA carboxylase. To elucidate the exact details of the protein-protein interactions in the biotinylation function, the C-terminal half fragment of BCCP (BCCPDeltaN76), the R48A mutant of BPL (BPL*) and the R48A K111A double mutant of BPL (BPL**), all of which are from Pyrococcus horikoshii OT3, have been expressed, purified and successfully cocrystallized. Cocrystals of the BPL*-BCCPDeltaN76 and BPL**-BCCPDeltaN76 complexes as well as crystals of BPL*, BPL** and BCCPDeltaN76 were obtained by the oil-microbatch method using PEG 20 000 as a precipitant at 295 K. Complete X-ray diffraction data sets for BPL*-BCCPDeltaN76 and BPL**-BCCPDeltaN76 crystals were collected at 100 K to 2.7 and 2.0 A resolution, respectively, using synchrotron radiation. They belong to the monoclinic space group P2(1), with similar unit-cell parameters a = 69.85, b = 63.12, c = 75.64 A, beta = 95.9 degrees . Assuming two subunits of the complex per asymmetric unit gives a V(M) value of 2.45 A(3) Da(-1) and a solvent content of 50%.

Pyrimidine nucleoside phosphorylase (PYNP) catalyzes the reversible phosphorolysis of pyrimidines in the nucleotide-synthesis salvage pathway. In order to study the structure-thermostability relationship of this enzyme, PYNP from the extreme thermophile Thermus thermophilus HB8 (TTHA1771) has been cloned, overexpressed and purified. The TTHA1771 protein was crystallized at 291 K using the oil-microbatch method with PEG 4000 as a precipitant. A native data set was collected to 1.8 A resolution using synchrotron radiation. The crystal belongs to the monoclinic space group P2(1), with unit-cell parameters a = 58.83, b = 76.23, c = 103.86 A, beta = 91.3 degrees.

The putative thiamine-biosynthesis protein PH1313 from Pyrococcus horikoshii OT3 has been overexpressed and purified. Crystallization was performed by the oil-microbatch method using 28%(v/v) 2-methyl-2,4-pentanediol as a precipitant at 291 K. A native X-ray diffraction data set at 1.9 A resolution and a single anomalous dispersion data set from a selenomethionine-derivative crystal at 2.1 A resolution were collected using synchrotron radiation at 100 K. The native crystal belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 71.7, b = 71.2, c = 141.8 A.

6-Pyruvoyl tetrahydrobiopterin synthase (PTPS) catalyses the conversion of dihydroneopterin triphosphate to 6-pyruvoyl tetrahydropterin, the second of the three enzymatic steps in the synthesis of tetrahydrobiopterin from GTP. PH0634, a 13.51 kDa archaeal PTPS homologue from Pyrococcus horikoshii OT3, was overexpressed as native and selenomethionine-substituted protein and the purified protein was crystallized by the oil-microbatch method at 295 K. X-ray diffraction data were collected to 2.1 A resolution from the native crystal using synchrotron radiation at 100 K. The crystal belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 35.83, b = 95.71, c = 105.65 A. Threefold noncrystallographic symmetry was identified from self-rotation calculations. Assuming the presence of a trimer in the asymmetric unit, the solvent content is 45% (V(M) = 2.24 A3 Da(-1)). The selenomethionine-substituted crystal is isomorphous to the native crystal and diffracts X-rays to 2.9 A.

Phosphoglycerate mutases catalyze the interconversion of 2-phosphoglycerate and 3-phosphoglycerate in glycolysis and gluconeogenesis pathways. The archaeal phosphoglycerate mutase PH0037 from Pyrococcus horikoshii OT3 has been overexpressed in Escherichia coli and purified. Crystals were obtained using the oil-microbatch method at 291 K. A native data set extending to a resolution of 2.2 angstroms has been collected and processed in space group R32. Assuming the presence of a dimer in the asymmetric unit, the V(M) value is calculated to be 3.0 angstroms3 Da(-1), consistent with the dynamic light-scattering experiment result, which shows a dimeric state of the protein in solution. Molecular-replacement trials using the crystal structure of Bacilllus stearothermophilus phosphoglycerate mutase as a search model did not provide a satisfactory solution, indicating substantially different structures of these two phophoglycerate mutases.

Circadian (daily) protein clocks are found in cyanobacteria, where a complex of the KaiA, KaiB and KaiC proteins generates circadian rhythms. The 28.09 kDa KaiC homologue PH0284 protein from Pyrococcus horikoshii OT3 was cloned and expressed and the purified protein was crystallized by the oil-microbatch method at 295 K. X-ray diffraction data from the crystal were collected to 2.0 angstroms resolution using synchrotron radiation at 100 K. The crystal belongs to the trigonal space group P3(2)21, with unit-cell parameters a = b = 96.06, c = 298.90 angstroms. Assuming the presence of one hexamer in the asymmetric unit gives a V(M) value of 2.36 angstroms3 Da(-1) and a solvent content of 47.9%. A cocrystal with ATP was prepared and a diffraction data set was collected at 2.3 angstroms resolution.

GTPases are involved in diverse cellular functions including cell proliferation, cytoskeleton organization and intracellular traffic. The putative GTPase PH0525 from Pyrococcus horikoshii OT3 has been overexpressed in Escherichia coli and purified. Two distinct crystal forms were grown by the microbatch method at 291 K using a very high protein concentration (80 mg ml(-1)). Native data sets extending to resolutions of 2.3 and 2.4 A have been collected and processed in space groups P2(1) and C222(1), respectively. Assuming the presence of one monomer per asymmetric unit gives VM values of 2.6 and 2.4 A3 Da(-1) for the P2(1) and C222(1) forms, respectively, which is consistent with dynamic light-scattering experiments, which show a monomeric state of the protein in solution.

Biotin-protein ligase is an enzyme that catalyzes the ATP-dependent biotinylation of a specific lysine residue in acetyl-CoA carboxylase. The biotin-protein ligase from Pyrococcus horikoshii OT3 has been cloned, overexpressed and purified. Crystallization was performed by the microbatch method or the vapour-diffusion method using PEG 2000 as a precipitant at 295 K. X-ray diffraction data have been collected to 1.6 A resolution from a native crystal and to 1.55 A resolution from a selenomethionine-derivative crystal for multiple anomalous dispersion phasing using synchrotron radiation at 100 K. The native crystal belongs to the monoclinic space group P2(1), with unit-cell parameters a = 38.601, b = 78.264, c = 70.147 A, beta = 101.48 degrees. Assuming a homodimer per asymmetric unit gives a VM value of 2.14 A3 Da(-1) and a solvent content of 42.5%. Cocrystals with biotin, ADP and biotinyl-5'-AMP were prepared and diffraction data sets were collected to 1.6, 1.6 and 1.45 A resolution, respectively.

The vacuole-type ATPases in eukaryotic cells translocate protons across various biological membranes including the vacuolar membrane by consuming ATP molecules. The E subunit of the multisubunit complex V-ATPase from Pyrococcus horikoshii OT3, which has a molecular weight of 22.88 kDa, has been cloned, overexpressed in Escherichia coli, purified and crystallized by the microbatch method using PEG 4000 as a precipitant at 296 K. A data set to 1.85 A resolution with 98.8% completeness and an Rmerge of 6.5% was collected from a single flash-cooled crystal using synchrotron radiation. The crystal belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 52.196, b = 55.317, c = 77.481 A, and is most likely to contain one molecule per asymmetric unit.