Search

A device to grease a 24-well crystallization plate can be easily made with a disposable plastic syringe and a sample-retention vial from a centrifugal filter device. It takes only 2 min to grease one plate with the device.

Asymmetric synthesis of [1S, 2S, 3R, 4R]-2, 3-dihydroxy-4-hydroxymethylcyclopent-1-ylmalonate (its racemic form is already known as a versatile building block for carbocyclic C-nucleosides) was achieved by Diels-Alder reaction of cyclopentadiene with di-l-menthyl acetoxymethylenemalonate, followed by retrograde aldol C-C bond fission under reductive conditions. Asymmetric induction in Diels-Alder reactions using the chiral dienophile and its nor-acetoxy derivative is discussed from a mechanistic viewpoint and a new concept for asymmetric induction is proposed.

SCO7518 is a protein of unknown function from Streptomyces coelicolor A3(2) that has been classified into the TetR transcriptional regulator family. In this study, a crystal structure of SCO7518 was determined at 2.29Å resolution. The structure is a homodimer of protomers that comprise an N-terminal DNA-binding domain and a C-terminal dimerization and regulatory domain, and possess a putative ligand-binding cavity. Genomic systematic evolution of ligands by exponential enrichment and electrophoretic mobility shift assays revealed that SCO7518 specifically binds to an operator sequence located upstream of the sco7519 gene, which encodes a maltose O-acetyltransferase. These results suggest that SCO7518 is a transcriptional repressor of sco7519 expression.

The three-dimensional structure of omega-amino acid:pyruvate aminotransferase from Pseudomonas sp. F-126, an isologous alpha 4 tetramer containing pyridoxal 5'-phosphate (PLP) as a cofactor, has been determined at 2.0 A resolution. The diffraction data were collected with a newly developed Weissenberg camera with a Fuji Imaging Plate, using synchrotron radiation. The mean figure-of-merit was 0.57. The subunit is rich in secondary structure and comprises two domains. PLP is located in the large domain. The high homology in the secondary structure between this enzyme and aspartate aminotransferase strongly indicates that these two types of enzymes have evolved from a common ancestor.

A totally new type of fully automatic Weissenberg data-collection system called ‘‘Galaxy’’ was developed and was installed at the Photon Factory. This automatic data collection system consists of a rotated-inclined focusing monochromator, a screenless Weissenberg type camera, an image reader, an eraser, a cassette transportation mechanism, a control console and a safety and high-speed computer network system linking a control console, data processing computers and data servers. The special characteristics of this system are a Weissenberg camera with a fully cylindrical cassette which can be rotated to exchange a frame, a maximum number of 36 images to be recorded in an IP cassette, and a very high speed IP reader with five reading heads. Since the frame exchange time is only a few seconds, this system is applicable for time-resolved protein crystallography at seconds or minutes of time-scale. # 2001 Elsevier Science B.V. All rights reserved. PACS: 07.85.Qe

A new single-crystal focusing monochromator for protein crystallography has been developed. In order to achieve simultaneous tuning of the beam demagnification rate and the radius of curvature for focusing over a wide wavelength range, the surface of an inclined monochromator was cylindrically bent. The monochromator is able to tune these two parameters simultaneously with a single rotation of the crystal about the azimuthal axis. A new monochromator incorporating this idea has been developed for beamline BL6B at the Photon Factory. The monochromator was designed for use in the wavelength range 0.87–1.90 Å, and beam focusing was tested at wavelengths of 1.04, 1.38 and 1.74 Å.

Le compose du titre est prepare a partir du L-menthol et de la dimethyl-2,2 hydroxymethylene-5 dioxanne-1,3 dione-4,6. Il reagit avec le cyclopentadiene pour donner un acetoxy-3 norbornene-5 dicarboxylate de menthyle qui reagit lui-meme avec NaBH 4 pour donner un derive de cyclopenta dioxole, analogue de C-nucleoside

It has been an earnest desire of protein crystallographers to collect fast, accurate, high resolution diffraction data from protein crystals, preferably with exposure time as short as possible. In order to meet this challenge, a new type of Weissenberg camera has been developed for the recording of diffraction intensity from protein crystals using synchrotron radiation. The BL6A2 line has a plane‐bending mirror designed by Y. Sato. The optical bench with triangular tilt‐cut Si crystal monochromator was designed by N. Kamiya and was installed in the BL6A2 hutch. The Weissenberg camera was set on the 2θ arm of the optical bench. This camera can be used with Fuji Imaging Plate (IP) as an x‐ray detector, and the reading out of the image from the IP is carried out by using BA100. The characterization of this system was carried out using the native crystal of chicken gizzard G‐actin DNase I complex and its Yb3+, PCMB, indium, and FMA derivatives. Since these crystals are very sensitive for x rays, the resolutio...

C-type lysozyme catalyzes the hydrolysis of peptidoglycan of bacterial cell wall. Most of C-type lysozymes express to protect body against bacterial infection. However, ruminants and some leaf-eating animals have evolved their lysozyme as digestive enzyme. They recruit bacteria which ferment cellulose in the foregut, and digest the bacteria by lysozyme in the true stomach to obtain nutrient. Digestive lysozyme has acquired some properties, such as low optimal pH, and resistance to protease and acid hydrolysis. The structural basis for these properties still remains unclear. In this investigation, we have obtained the crystallographic structure of bovine stomach lysozyme (BSL). This is the first report on the structure of vertebrate digestive lysozyme. We have carried out the denaturant-unfolding experiment and revealed that BSL has high structural stability at acidic pH compared to non-digestive (hen egg-white) lysozyme. The structural stability in acidic solution would be related to the pepsin resistance which was previously reported for BSL. The crystal structure of BSL suggested that negatively charged surfaces, a shortened loop, and salt bridges should provide the structural stability.