A front-face 'Si synthase' engineered from a retaining 'double-S2' hydrolase.

Si-like mechanisms, which involve front-face leaving group departure and nucleophile approach, have been observed experimentally and computationally in chemical and enzymatic substitution at α-glycosyl electrophiles. Since Si-like, S1 and S2 substitution pathways can be energetically comparable, engineered switching could be feasible. Here, engineering of Sulfolobus solfataricus β-glycosidase, which originally catalyzed double S2 substitution, changed its mode to Si-like.

STRU-cloning: a fast, inexpensive and efficient cloning procedure applicable to both small scale and structural genomics size cloning.

We have developed a Single-Tube Restriction-based Ultrafiltration (STRU) cloning procedure that updates traditional ligation-dependent cloning to challenge the newer, faster and more efficient ligation-free techniques and could make it the method of choice. STRU-cloning employs centrifugal filter units with membrane of suitable cut off to remove small unwanted DNA fragments created during restriction of plasmids or PCR products. Heat inactivation, of restriction enzymes, followed by DNA ligation is then performed on the filtrate.

MptpB, a virulence factor from Mycobacterium tuberculosis, exhibits triple-specificity phosphatase activity.

Bacterial pathogens have developed sophisticated mechanisms of evading the immune system to survive in infected host cells. Central to the pathogenesis of Mycobacterium tuberculosis is the arrest of phagosome maturation, partly through interference with PtdIns signalling. The protein phosphatase MptpB is an essential secreted virulence factor in M.

Small-angle X-ray scattering reveals the solution structure of a bacteriophytochrome in the catalytically active Pr state.

Phytochromes are light-sensing macromolecules that are part of a two component phosphorelay system controlling gene expression. Photoconversion between the Pr and Pfr forms facilitates autophosphorylation of a histidine in the dimerization domain (DHp). We report the low-resolution structure of a bacteriophytochrome (Bph) in the catalytic (CA) Pr form in solution determined by small-angle X-ray scattering (SAXS).