A New IL-6-Inducing Mechanism in Cancer with New Therapeutic Possibilities.

: Interleukin-6 is dysregulated in multiple pathological conditions, e.g., cancer and inflammatory diseases.

Structural genomics studies of human caries pathogen Streptococcus mutans.

Gram-positive bacterium Streptococcus mutans is the primary causative agent of human dental caries. To better understand this pathogen at the atomic structure level and to establish potential drug and vaccine targets, we have carried out structural genomics research since 2005. To achieve the goal, we have developed various in-house automation systems including novel high-throughput crystallization equipment and methods, based on which a large-scale, high-efficiency and low-cost platform has been establish in our laboratory.

Probing allostery through DNA.

Allostery is well documented for proteins but less recognized for DNA-protein interactions. Here, we report that specific binding of a protein on DNA is substantially stabilized or destabilized by another protein bound nearby. The ternary complex's free energy oscillates as a function of the separation between the two proteins with a periodicity of ~10 base pairs, the helical pitch of B-form DNA, and a decay length of ~15 base pairs.

Preliminary crystallographic studies of purine nucleoside phosphorylase from the cariogenic pathogen Streptococcus mutans.

The punA gene of the cariogenic pathogen Streptococcus mutans encodes purine nucleoside phosphorylase (PNP), which is a pivotal enzyme in the nucleotide-salvage pathway, catalyzing the phosphorolysis of purine nucleosides to generate purine bases and alpha-ribose 1-phosphate. In the present work, the PNP protein was expressed in Escherichia coli strain BL21 (DE3) in a soluble form at a high level. After purification of the PNP enzyme, the protein was crystallized using the sitting-drop vapour-diffusion technique; the crystals diffracted to 1.

Bioinformatics and structural characterization of a hypothetical protein from Streptococcus mutans: implication of antibiotic resistance.

As an oral bacterial pathogen, Streptococcus mutans has been known as the aetiologic agent of human dental caries. Among a total of 1960 identified proteins within the genome of this organism, there are about 500 without any known functions. One of these proteins, SMU.

Solid-liquid interface method (SLIM): a new crystallization method for proteins.

Despite impressive advances in theories, methods and technologies, crystallization still remains a serious bottleneck in structural determination of macromolecules. Here we present a novel solid-liquid interface method (SLIM) for protein crystallization, based on the pre-adding and drying of a crystallization reagent, and thereafter the dispensing of a protein solution to the dried media to initiate crystallization from the solid-liquid interface. Not only quick and easy to perform, the method also allows for a less concentrated protein solution for setting up crystallization trials.

Structure of a fatty-acid-binding protein from Bacillus subtilis determined by sulfur-SAD phasing using in-house chromium radiation.

Sulfur single-wavelength anomalous dispersion (S-SAD) and halide-soaking methods are increasingly being used for ab initio phasing. With the introduction of in-house Cr X-ray sources, these methods benefit from the enhanced anomalous scattering of S and halide atoms, respectively. Here, these methods were combined to determine the crystal structure of BsDegV, a DegV protein-family member from Bacillus subtilis.

Open-closed conformational change revealed by the crystal structures of 3-keto-L-gulonate 6-phosphate decarboxylase from Streptococcus mutans.

The 3-keto-L-gulonate 6-phosphate decarboxylase (KGPDC) catalyses the decarboxylation of 3-keto-L-gulonate 6-phosphate to L-xylulose in the presence of magnesium ions. The enzyme is involved in L-ascorbate metabolism and plays an essential role in the pathway of glucuronate interconversion. Crystal structures of Streptococcus mutans KGPDC were determined in the absence and presence of the product analog D-ribulose 5-phosphate.

An automated image-collection system for crystallization experiments using SBS standard microplates.

As part of a structural genomics platform in a university laboratory, a low-cost in-house-developed automated imaging system for SBS microplate experiments has been designed and constructed. The imaging system can scan a microplate in 2-6 min for a 96-well plate depending on the plate layout and scanning options. A web-based crystallization database system has been developed, enabling users to follow their crystallization experiments from a web browser.

A catalytic mechanism revealed by the crystal structures of the imidazolonepropionase from Bacillus subtilis.

Imidazolonepropionase (EC 3.5.2.

A large-scale, high-efficiency and low-cost platform for structural genomics studies.

A large-scale, high-efficiency and low-cost platform based on a Beckman Coulter Biomek FX and custom-made automation systems for structural genomics has been set up at Peking University, Beijing, People's Republic of China. This platform has the capacity to process up to 2000 genes per year for structural and functional analyses. Bacillus subtilis, a model organism for Gram-positive bacteria, and Streptococcus mutans, a major pathogen of dental caries, were selected as the main targets.