Potassium Linoleate (Isomerized) Satisfies the United States Environmental Protection Agency MB-05-16 for Hospital Disinfectant on Hard, Non-porous Surfaces.

Potassium conjugated linoleic acid or potassium linoleate (isomerized), 86 mM, satisfies the United States Environmental Protection Agency protocol hospital disinfectant for non-porous surfaces MB-05-16 with one-minute treatment. This stringent protocol requires separate preparations of (American Type Culture Collection 6538) and (American Type Culture Collection 15442) unstirred for 48 hours, submerging 10 mm polished cylinders in the culture, and placing for 45 minutes in a 37°C humidified chamber before treating. Since potassium linoleate (isomerized) also satisfies the United States Environmental Protection Agency protocol MB-35-00 for , this study establishes potassium linoleate (isomerized) as an effective cross-kingdom antimicrobial plant salt, soap, or cleanser.

Phosphorylation Regulates Functions of ZEB1 Transcription Factor.

ZEB1 transcription factor is important in both development and disease, including many TGFβ-induced responses, and the epithelial-to-mesenchymal transition (EMT) by which many tumors undergo metastasis. ZEB1 is differentially phosphorylated in different cell types; however the role of phosphorylation in ZEB1 activity is unknown. Luciferase reporter studies and electrophoresis mobility shift assays (EMSA) show that a decrease in phosphorylation of ZEB1 increases both DNA-binding and transcriptional repression of ZEB1 target genes.

Porphyromonas gingivalis initiates a mesenchymal-like transition through ZEB1 in gingival epithelial cells.

The oral anaerobe Porphyromonas gingivalis is associated with the development of cancers including oral squamous cell carcinoma (OSCC). Here, we show that infection of gingival epithelial cells with P. gingivalis induces expression and nuclear localization of the ZEB1 transcription factor, which controls epithelial-mesenchymal transition.

Structural basis for the role of Asp-120 in metallo-beta-lactamases.

Metallo-beta-lactamases (mbetals) are zinc-dependent enzymes that hydrolyze a wide range of beta-lactam antibiotics. The mbetal active site features an invariant Asp-120 that ligates one of the two metal ions (Zn2) and a metal-bridging water/hydroxide (Wat1). Previous studies show that substitutions at Asp-120 dramatically affect mbetal activity, but no consensus exists as to its role in beta-lactam turnover.

Mutational analysis of the stator subunit E of the yeast V-ATPase.

Subunit E is a component of the peripheral stalk(s) that couples membrane and peripheral subunits of the V-ATPase complex. In order to elucidate the function of subunit E, site-directed mutations were performed at the amino terminus and carboxyl terminus. Except for S78A and D233A/T202A, which exhibited V(1)V(o) assembly defects, the function of subunit E was resistant to mutations.

The binding of iron and zinc to glyoxalase II occurs exclusively as di-metal centers and is unique within the metallo-beta-lactamase family.

Cytosolic glyoxalase 2 (GLX2-2) from Arabidopsis thaliana is a metalloenzyme that has been shown to bind a mixture of Zn, Fe, or Mn when produced in cells grown in rich media. In an effort to prepare metal-enriched samples, GLX2-2 was over-expressed in minimal media containing either Zn, Fe, or Mn. The resulting enzymes bound an average of 1 equivalent of metal ion and were partially enriched with a specific metal ion.

Metal binding Asp-120 in metallo-beta-lactamase L1 from Stenotrophomonas maltophilia plays a crucial role in catalysis.

Metallo-beta-lactamase L1 from Stenotrophomonas maltophilia is a dinuclear Zn(II) enzyme that contains a metal-binding aspartic acid in a position to potentially play an important role in catalysis. The presence of this metal-binding aspartic acid appears to be common to most dinuclear, metal-containing, hydrolytic enzymes; particularly those with a beta-lactamase fold. In an effort to probe the catalytic and metal-binding role of Asp-120 in L1, three site-directed mutants (D120C, D120N, and D120S) were prepared and characterized using metal analyses, circular dichroism spectroscopy, and presteady-state and steady-state kinetics.

Explaining the inhibition of glyoxalase II by 9-fluorenylmethoxycarbonyl-protected glutathione derivatives.

In an effort to probe the inhibition of glyoxalase II (GLX2-2) from Arabidopsis thaliana, a series of N- and S-blocked glutathione compounds containing 9-fluorenylmethoxycarbonyl (FMOC) and Cbz protecting groups were synthesized and tested. The di-FMOC and di-Cbz compounds were the best inhibitors of GLX2-2 with K(i) values of 0.89+/-0.

Characterization of monomeric L1 metallo-beta -lactamase and the role of the N-terminal extension in negative cooperativity and antibiotic hydrolysis.

The L1 metallo-beta-lactamase from Stenotrophomonas maltophilia is unique among this class of enzymes because it is tetrameric. Previous work predicted that the two regions of important intersubunit interaction were the residue Met-140 and the N-terminal extensions of each subunit. The N-terminal extension was also implicated in beta-lactam binding.

Probing substrate binding to metallo-beta-lactamase L1 from Stenotrophomonas maltophilia by using site-directed mutagenesis.

Background: The metallo-beta-lactamases are Zn(II)-containing enzymes that hydrolyze the beta-lactam bond in penicillins, cephalosporins, and carbapenems and are involved in bacterial antibiotic resistance. There are at least 20 distinct organisms that produce a metallo-beta-lactamase, and these enzymes have been extensively studied using X-ray crystallographic, computational, kinetic, and inhibition studies; however, much is still unknown about how substrates bind and the catalytic mechanism. In an effort to probe substrate binding to metallo-beta-lactamase L1 from Stenotrophomonas maltophilia, nine site-directed mutants of L1 were prepared and characterized using metal analyses, CD spectroscopy, and pre-steady state and steady state kinetics.