The quinoprotein methanol dehydrogenase (MDH) contains a Ca2+ ion at the active site. Ca(2-)-free enzyme (from a processing mutant) was used to obtain enzyme containing Sr2+ or Ba2+, the Ba(2+)-MDH being the first enzyme to be described in which a Ba2+ ion functions at the active site. The activation energy for oxidation of methanol by Ba(2+)-MDH is less than half that of the reaction catalysed...

Density functional theory (DFT) at the generalised gradient approximation level is employed within the periodic electrostatic embedded cluster method (PEECM) to model the brucite (0001) surface. Three representative studies are then used to demonstrate the reliability of the PEECM for the description of the interactions of various ionic species with the layered Mg(OH)2 structure, and its perfor...

Seawater reverse osmosis (SWRO) desalination plants generate high volumes of concentrates, which contain, in addition to major salts, some elements growing interest minor concentrations. This is the case lithium, highly demanded battery industry. In this work, separation Li+ from model SWRO brines has been evaluated by obtaining extraction curves with combination extractants DBM•TOPO and FDOD•T...

Microencapsulation has become a common technique in the production of controlled release dosage forms. Many results have been reported, concerning the use of alginate beads as controlled release drug formulations. Alginate has a unique gel-forming property in the presence of multivalent cations, in an aqueous medium. Ibuprofen is an excellent analgesic and antipyretic, non-steroidal anti-inflam...

Changes in [Mg2+] in a millimolar range have a significant inverse effect on the Ca2+- (or Sr2+)activated tension generation of skeletal muscle fibers. Single frog (Rana pipiens) semitendinosus muscle fibers were "skinned" (sarcolemma removed) and contracted isometrically in bathing solutions of varying [Ca2+] or [Sr2+] and [Mg2+] but a constant pH, [MgATP2-], [K+], [CP2-], [CPK], and ionic str...

Serine/arginine-rich proteins (SR proteins) are a family of nuclear factors that play important roles in both constitutive and regulated precursor mRNA splicing. The domain rich in arginine/serine (RS) repeats (RS domain) serves as both a nuclear and subnuclear localization signal. We previously identified an importin beta family protein, transportin-SR2 (TRN-SR2), that specifically interacts w...

Viroporins are small virus-encoded ion channel proteins. Most viroporins are monovalent selective cation channels, with few showing the ability to conduct divalent cations, like calcium (Ca2+). Nevertheless, some viroporins are known to disrupt host cell Ca2+ homeostasis, which is critical for virus replication and pathogenesis. Rotavirus nonstructural protein 4 (NSP4) is an endoplasmic reticul...

Myxococcus xanthus fibrils are cell surface-associated structures composed of roughly equal amounts of polysaccharide and protein. The level of M. xanthus polysaccharide production under different conditions in the wild type and in several mutants known to have alterations in fibril production was investigated. Wild-type exopolysaccharide increased significantly as cells entered the stationary ...