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In bacteria and eukaryotes, the last two steps of de novo purine biosynthesis are catalyzed by bifunctional purine-biosynthesis protein (PurH), which is composed of two functionally independent domains linked by a flexible region. The N-terminal domain possesses IMP cyclohydrolase activity and the C-terminal domain possesses aminoimidazole-4-carboxamide ribonucleotide transformylase activity. This study reports the expression, purification, crystallization and preliminary X-ray crystallographic analysis of PurH from Escherichia coli with an N-terminal His6 tag. The crystals diffracted to a maximum resolution of 3.05 Å and belonged to the monoclinic space group P21, with unit-cell parameters a = 76.37, b = 132.15, c = 82.64 Å, β = 111.86°. [ABSTRACT FROM AUTHOR]

The Gos1 protein (Golgi SNAP receptor complex member 1) is involved in the SNARE complex, which is the core machinery that drives membrane fusion between cargo-carrying vesicles and their target membranes in the secretory and endocytic pathways in yeast. Truncated versions of the Gos1 protein from Saccharomyces cerevisiae were cloned, expressed, purified and crystallized. The crystal belonged to space group P212121, with unit-cell parameters a = 39.67, b = 43.58, c = 81.94 Å, α = β = γ = 90°. An X-ray diffraction data set was collected at 100 K to 1.63 Å resolution. Matthews coefficient ( VM) calculations suggest that one molecule is present in the asymmetric unit, corresponding to a solvent content of ∼55%. [ABSTRACT FROM AUTHOR]

Adenylate kinase plays a very important role in regulating adenylate species in the cell. Methanocaldococcus jannaschii is a rich resource of unique enzymes. Here, MJ0458, an adenylate kinase from M. jannaschii, was crystallized. A set of X-ray diffraction data to 2.70 Å resolution was collected on beamline BL-17U of the Shanghai Synchrotron Radiation Facility (SSRF). The crystal belonged to space group P41212 or P43212. The unit-cell parameters were a = b = 76.18, c = 238.70 Å, α = β = γ = 90°. [ABSTRACT FROM AUTHOR]

Synaptotagmin acts as the Ca2+ sensor for neural and endocrine exocytosis. Synaptotagmin 5 has been demonstrated to play a key role in the acquisition of cathepsin D and the vesicular proton ATPase and in Ca2+-dependent insulin exocytosis. The C2 domains modulate the interaction of synaptotagmin with the phospholipid bilayer of the presynaptic terminus and effector proteins such as the SNARE complex. This study reports the cloning, expression in Escherichia coli, purification, crystallization and preliminary X-ray analysis of the C2A domain of human synaptotagmin 5 with an N-terminal His6 tag. The crystals diffracted to 1.90 Å resolution and belonged to the hexagonal space group P65, with unit-cell parameters a = b = 93.97, c = 28.05 Å. A preliminary model of the protein structure has been built and refinement of the model is ongoing. [ABSTRACT FROM AUTHOR]

In Saccharomyces cerevisiae, TRM6 and TRM61 compose a tRNA methyltransferase which catalyzes the methylation of the N1 of adenine at position 58 in tRNAs, especially initiator methionine tRNA. TRM61 is the subunit that binds S-adenosyl- l-methionine and both subunits contribute to target tRNA binding. In order to elucidate the catalytic mechanism of TRM6-TRM61 and the mode of interaction between the two subunits, expression, purification, crystallization and X-ray diffraction analysis of the TRM6-TRM61 complex were performed in this study. The crystals diffracted to 2.80 Å resolution and belonged to the trigonal space group P3121 or P3221, with unit-cell parameters a = b = 139.14, c = 101.62 Å. [ABSTRACT FROM AUTHOR]

Nitrogenases are protein complexes that are only found in Azotobacter and are required for biological nitrogen fixation. They are made up of a nitrogenase, which is a NifD2/NifK2 heterotetramer, and a nitrogenase reductase, which is a homodimer of NifH. Many homologues of nitrogenase have been found in various non-nitrogen-fixing prokaryotes; in particular, they are found in all known methanogens. This indicates that these homologues may play a role in methane production. Here, the cloning of NifH2, a homologue of the NifH nitrogenase component, from Methanocaldococcus jannaschii ( MjNifH2) and its expression in Escherichia coli with a polyhistidine tag, purification and crystallization are described. MjNifH2 crystals were obtained by the hanging-drop vapour-diffusion method and diffracted to a resolution limit of 2.85 Å. The crystals belonged to space group P2, with unit-cell parameters a = 64.01, b = 94.38, c = 98.08 Å, α = γ = 90, β = 98.85°. [ABSTRACT FROM AUTHOR]

Escherichia coli YeaD (ecYeaD) is suggested to be a member of the galactose mutarotase-like superfamily. Galactose mutarotase is an enzyme that converts α-galactose to β-galactose. The known structures of these galactose mutarotase-like proteins are similar to those of galactose mutarotases, with the catalytic residues being conserved, but there are some differences between them in the substrate-binding pocket. In order to reveal the specificity of ecYeaD, a three-dimensional structure is essential. Full-length ecYeaD with an additional 6×His tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 4000 as a precipitant at 283 K. An X-ray diffraction data set was collected to a resolution of 1.9 Å from a single flash-cooled crystal that belonged to space group P212121. [ABSTRACT FROM AUTHOR]

The histone chaperone SET encoded by the SET gene, which is also known as template-activating factor Iβ (TAF-Iβ), is a multifunctional molecule that is involved in many biological phenomena such as histone binding, nucleosome assembly, chromatin remodelling, replication, transcription and apoptosis. A truncated SET/TAF-IβΔN protein that lacked the first 22 residues of the N-terminus but contained the C-terminal acidic domain and an additional His6 tag at the C-terminus was overexpressed in Escherichia coli and crystallized by the hanging-drop vapour-diffusion method using sodium acetate as precipitant at 283 K. The crystals diffracted to 2.7 Å resolution and belonged to space group P43212. [ABSTRACT FROM AUTHOR]