A method has been developed that combines electrospray ionization mass spectrometry with pH control to provide analysis of metals in native or reconstituted metallothioneins. These metalloproteins cooperatively bind seven divalent metal ions, most commonly Zn2+ and Cd2+. Since the protein is denatured and metal ions are lost below pH3, the pH of the electrospray solution is critical to successful results. The metal-free apoprotein was detected with its most abundant ions in a charge state of 6+, while the folded metallothionein-metal complexes were observed with lower charge states. The retention of seven metals in the molecular ions detected is consistent with the hypothesis that metallothionein retains its conformation in the gas phase. This mass spectrometric technique can be used to determine rapidly and accurately how many and what cations are incorporated per molecule of protein. Information about molar distributions and estimates of relative abundances of various complexes in the sample can be acquired in a single measurement.

Fluorescent core-shell CdTe@SiO 2 particles with controllable particle sizes were prepared via a reverse microemulsion method by hydrolyzing tetraethyl orthosilicate within microwater droplets. Aqueous CdTe nanocrystals and CdS nanocrystals stabilized by different types of thiol molecules were prepared for elucidating the mechanism leading to the core-shell structures. Photo-oxidation experiments were performed to show the enhancement effect of the silica shell on the photostability of the CdTe nanocrystals encapsulated. Further surface modifications were also performed for grafting amino groups on the surface of the resultant fluorescent CdTe@SiO 2 particles.

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Rabbit liver metallothionein-2 is shown to form covalent bonds with the anticancer agent melphalan, in support of the hypothesis that covalent sequestration by metallothionein constitutes one mechanism for the cross-resistance acquired by cancer patients to therapeutic alkylating agents. Among 20 cysteines in the 2-domain protein, 89% of the first alkylation reaction occurs with 2 that cochelate a zinc cation in the carboxy domain. Computer-supported docking studies indicate a favorable binding site for melphalan near these cysteine sulfhydryl groups. Although folded metallothionein-2 is resistant to trypsin cleavage, alkylation by 1 mol of melphalan allows cleavage by trypsin between the two globular domains.

Plant protein phosphatase 2Cs (PP2Cs) play crucial roles in phytohormone signaling, developmental processes, and both biotic and abiotic stress responses. However, little research has been conducted on the PP2C gene family in hexaploid wheat ( Triticum aestivum L.), which is an important cereal crop. In this study, a genome-wide investigation of TaPP2C gene family was performed. A total of 257 homoeologs of 95 TaPP2C genes were identified, of which 80% of genes had all the three homoeologs across A, B, and D subgenomes. Domain analysis indicated that all the TaPP2C homoeologs harbored the type 2C phosphatase domains. Based on the phylogenetic analysis, TaPP2Cs were divided into 13 groups (A-M) and 4 single branches, which corresponded to the results of gene structure and protein motif analyses. Results of chromosomal location and synteny relationship analysis of TaPP2C homoeologs revealed that known chromosome translocation events and pericentromeric inversions were responsible for the formation of TaPP2C gene family. Expression patterns of TaPP2C homoeologs in various tissues and under diverse stress conditions were analyzed using publicly available RNA-seq data. The results suggested that TaPP2C genes regulate wheat developmental processes and stress responses. Homoeologous expression patterns of TaPP2C triad homoeologs from A, B, and D subgenomes, revealed expression bias within triads under the normal condition, and variability in expression under different stress treatments. Quantitative real-time PCR (qRT-PCR) analysis of eight TaPP2C genes in group A revealed that they were all up-regulated after abscisic acid treatment. Some genes in group A also responded to other phytohormones such as methyl jasmonate and gibberellin. Yeast two-hybrid assays showed that group A TaPP2Cs also interacted with TaSnRK2.1 and TaSnRK2.2 from subclass II, besides with subclass III TaSnRK2s. TaPP2C135 in group A was transformed into Arabidopsis and germination assay revealed that ectopic expression of TaPP2C135 in Arabidopsis enhanced its tolerance to ABA. Overall, these results enhance our understanding of the function of TaPP2Cs in wheat, and provide novel insights into the roles of group A TaPP2Cs. This information will be useful for in-depth functional analysis of TaPP2Cs in future studies and for wheat breeding.

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Three silver(I) cluster-based coordination polymers, namely, [Ag3(podc)(H2O)2]·2H2O (1), [Ag2(pidc)] (2), and [Ag2(pidc)(H2O)] (3) (H3podc = 3,5-pyrazoledicarboylic acid and H2pidc = 2,3-pyrazinedicarboxylic acid) have been synthesized. Among them, 1 consists of stairlike one-dimensional chains with boxlike units as well as the zigzag tetranuclear silver(I) cluster subunits [Ag···Ag 2.778(1) and 3.230(1) Å]; 2 features new parallel single-strand silver(I) helices that propagate by the 41-screw symmetry with short Ag···Ag contacts [Ag2···Ag2 3.158(1) Å] along the c-axis and display the same handedness, while 3 features hexagonal Ag4(μ2-O)2 cores, in which the Ag···Ag separation is 3.150(2) Å. These complexes display room temperature photoluminescence in the blue/green region, which may be assigned to an admixture of ligand-to-metal charge transfer and metal-centered (d−s/d−p) transitions.