Isolation of antiplasmodial anthraquinones from Kniphofia ensifolia, and synthesis and structure-activity relationships of related compounds.

Bioassay-guided separation of the South African plant Kniphofia ensifolia for antiplasmodial activity led to the isolation of two new anthraquinones, named kniphofiones A and B (3 and 4), together with three known bioactive anthraquinone monomers (1, 2 and 5), and four known bisanthraquinones (6-9). The structures of the two new compounds were elucidated based on analyses of their 1D and 2D NMR spectra and mass spectrometric data. The dimeric compounds 6 and 7 displayed the strongest antiplasmodial activity among all the isolated compounds, with IC₅₀ values of 0.

Sinorhizobium meliloti 1021 loss-of-function deletion mutation in chvI and its phenotypic characteristics.

Bacterial two-component regulatory systems (TCS) are common components of complex regulatory networks and cascades. In Sinorhizobium meliloti, the TCS ExoS/ChvI controls exopolysaccharide succinoglycan production and flagellum biosynthesis. Although this system plays a crucial role in establishing the symbiosis between S.

Expression, purification, and circular dichroism analysis of human CDK9.

The human cyclin-dependent kinase 9 (CDK9) protein was expressed in E. coli BL21 using the pET23a vector at 30 degrees C. Several milligrams of protein were purified from soluble fraction using ionic exchange and ATP-affinity chromatography.

DAHP synthase from Mycobacterium tuberculosis H37Rv: cloning, expression, and purification of functional enzyme.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains the leading cause of mortality due to a bacterial pathogen. According to the 2004 Global TB Control Report of the World Health Organization, there are 300,000 new cases per year of multi-drug resistant strains (MDR-TB), defined as resistant to isoniazid and rifampicin, and 79% of MDR-TB cases are now "super strains," resistant to at least three of the four main drugs used to treat TB. Thus there is a need for the development of effective new agents to treat TB.

Selection of an Escherichia coli host that expresses mutant forms of Mycobacterium tuberculosis 2-trans enoyl-ACP(CoA) reductase and 3-ketoacyl-ACP(CoA) reductase enzymes.

Tuberculosis (TB) still remains a worldwide health concern. Efforts to understand the complex biology of Mycobacterium tuberculosis, the causative agent of TB, are important for new antitubercular drug development. Despite the completion of the genome sequence and the development of new genetic tools to manipulate this organism, the availability of sufficient amounts of mycobacterial proteins still remains an essential and laborious step to study the biochemical features of this pathogen.

Docking and small angle X-ray scattering studies of purine nucleoside phosphorylase.

Docking simulations have been used to assess protein complexes with some success. Small angle X-ray scattering (SAXS) is a well-established technique to investigate protein spatial configuration. This work describes the integration of geometric docking with SAXS to investigate the quaternary structure of recombinant human purine nucleoside phosphorylase (PNP).