Metalloproteomics: high-throughput structural and functional annotation of proteins in structural genomics

A high-throughput method for measuring transition metal content based on quantitation of X-ray fluorescence signals was used to analyze 654 proteins selected as targets by the New York Structural GenomiX Research Consortium. Over 10% showed the presence of transition metal atoms in stoichiometric amounts; these totals as well as the abundance distribution are similar to those of the Protein Data Bank. Bioinformatics analysis of the identified metalloproteins in most cases supported the metalloprotein annotation; identification of the conserved metal binding motif was also shown to be useful in verifying structural models of the proteins. Metalloproteomics provides a rapid structural and functional annotation for these sequences and is shown to be approximately 95% accurate in predicting the presence or absence of stoichiometric metal content. The project's goal is to assay at least 1 member from each Pfam family; approximately 500 Pfam families have been characterized with respect to transition metal content so far.     

Differential inhibition of inducible T cell cytokine secretion by potent iron chelators

Effector functions and proliferation of T helper (Th) cells are influenced by cytokines in the environment. Th1 cells respond to a synergistic effect of interleukin-12 (IL-12) and interleukin-18 (IL-18) to secrete interferon-gamma (IFN-gamma). In contrast, Th2 cells respond to interleukin-4 (IL-4) to secrete IL-4, interleukin-13 (IL-13), interleukin-5 (IL-5), and interleukin-10 (IL-10). The authors were interested in identifying nonpeptide inhibitors of the Th1 response selective for the IL-12/IL-18-mediated secretion of IFN-gamma while leaving the IL-4-mediated Th2 cytokine secretion relatively intact. The authors established a screening protocol using human peripheral blood mononuclear cells (PBMCs) and identified the hydrazino anthranilate compound 1 as a potent inhibitor of IL-12/IL-18-mediated IFN-gamma secretion from CD3(+) cells with an IC(50) around 200 nM. The inhibitor was specific because it had virtually no effect on IL-4-mediated IL-13 release from the same population of cells. Further work established that compound 1 was a potent intracellular iron chelator that inhibited both IL-12/IL-18- and IL-4-mediated T cell proliferation. Iron chelation affects multiple cellular pathways in T cells. Thus, the IL-12/IL-18-mediated proliferation and IFN-gamma secretion are very sensitive to intracellular iron concentration. However, the IL-4-mediated IL-13 secretion does not correlate with proliferation and is partially resistant to potent iron chelation.     

Isolation, purification and characterization of collagenase from hepatopancreas of the land snail Achatina fulica

Collagenase (matrix metalloproteinase-1, EC:3.4.24.7) was isolated from the hepatopancreas of Achatina fulica and characterized for its enzymatic activity and immunological properties. Procollagenase was isolated using ammonium sulphate precipitation and gel filtration, followed by purification by reverse-phase high performance liquid chromatography in the presence of trifluoroacetic acid and by dialysis in neutral buffer. In the presence of SDS and beta-mercaptoethanol, the procollagenase resolved into two subunits with molecular masses of 63 and 28 kDa, respectively. The 63 kDa fragment retained its ability to bind and degrade gelatin, but the 28 kDa was inactive. Analysis by 2D gel electrophoresis revealed that the 63 kDa fragment was basic (pIs 7.6, 7.8 and 8.15), while the 28 kDa fragment was acidic (pI 4.7 and 5.1). Western blot analysis confirmed the identity of collagenase, as only matrix metalloproteinase-1 rabbit antibodies against human matrix metalloproteinase-1 (N-terminal region) recognized both the isolated procollagenase and the 63 kDa fragment.     

Antitubercular agents. Part 1: synthesis of phthalimido- and naphthalimido-linked phenazines as new prototype antitubercular agents

The preparation and antitubercular properties of a series of phthalimido- and naphthalimido-linked phenazines are described. Some of these new compounds inhibited the growth of Mycobacterium tuberculosis ATCC 27294, Mycobacterium avium ATCC 49601, Mycobacterium intracellulare ATCC 13950 and some clinical isolates.     

Comparison of the anti-influenza virus activity of cyclopentane derivatives with oseltamivir and zanamivir in vivo

Cyclopentane derivatives, designated as BCX-1812, BCX-1827, BCX-1898, and BCX-1923, were tested in parallel with oseltamivir carboxylate and zanamivir for the in vivo activity in mice infected with A/Turkey/Mas/76 X A/Beijing/32/92 (H6N2) influenza virus. The compounds were tested orally and intranasally at different dose levels. BCX-1812, BCX-1827, and BCX-1923 showed more than 50% protection at 1mg/kg/day dose level on oral treatment. The intranasal treatment was 100% effective even at 0.01 mg/kg/day for all four compounds. On comparison with oseltamivir carboxylate and zanamivir, these four cyclopentane derivatives have shown equal or better efficacies. The synthesis of two new compounds, BCX-1898 and BCX-1923, is also described.     

Synthesis of 9-[1-(substituted)-2-(phosphonomethoxy)ethyl]adenine derivatives as possible antiviral agents

Various C-1'-substituted acyclic N9 adenine nucleosides were prepared from 9-[(1-hydroxymethyl)(3-monomethoxytrityloxy)propyl]-N6-monomethoxytrityladenine. The hydroxymethyl was modified to the phosphonomethoxy derivative, and the 3-monomethoxytrityloxy was converted to hydroxyl, methoxy, azido, and amino. Other substituents, such as ethyl and ea-hydroxyethyl were also prepared. The resulting phosphonomethoxy derivatives were converted to prodrugs.     

Stereoselective synthesis of a ketohexofuranose from an aldohexopyranose by a [6+1-1] strategy

Ozonolysis of 2-acetoxymethyl-1,5-anhydro-3,4,6-tri-O-benzyl-2-deoxy-D-arabino-hex-1-enitol gave 1-O-acetyl-3,4,6-tri-O-benzyl-4-O-formyl-D-arabino-hex-2-ulose (5). Subsequent hydrolysis and acetylation of 5 provided 1,2-di-O-acetyl-3,4,6-tri-O-benzyl-D-fructofuranose 6 in excellent yield. This methodology allows specific deuteration at C-1 of a protected D-fructofuranose derivative. This approach therefore could serve as [6+1-1] formulation for hexose series inter-conversion, that is, aldohexopyranose to ketohexofuranose.     

Evidence for p62 aggregate formation: role in cell survival

The polyubiquitin-binding protein p62 has been shown to localize in aggregates common to several types of diseases. Here, we report that p62 forms independent fibrillar aggregates in vitro in a time- and concentration-dependent manner. FTIR spectra and ThT fluorescence assay of p62 reveals increased beta-sheet content as aggregates form compared to the native protein. The fibrillar nature of the aggregates was observed by transmission electron microscopy. Overexpression of p62 in HEK cells results in aggregate formation that may protect cells from apoptosis. Altogether, these results suggest that p62 fibrils may influence cell viability and indicates an important role for p62 in aggresome formation.     

Antiinflammatory and antiulcer activities of phytic acid in rats

Maximum antiinflammatory activity of phytic acid (PA) was seen at an oral dose of 150 mg/kg in the carrageenan induced rat paw edema model. Although PA showed ability to prevent denaturation of proteins, it showed less antiinflammatory activity than ibuprofen. Ability of PA to bring down thermal denaturation of proteins might be a contributing factor in the mechanism of action against inflammation. PA, at all the doses tested, showed significant protection from ulcers induced by ibuprofen, ethanol and cold stress, with a maximum activity at 150 mg/kg. There was a significant increase in gastric tissue malondialdehyde levels in ethanol treated rats but these levels decreased following PA pretreatment. Moreover, pretreatment with PA significantly inhibited various effects of ethanol on gastric mucosa, such as, reduction in the concentration of nonprotein sulfhydryl groups, necrosis, erosions, congestion and hemorrhage. These results suggested that gastro-protective effect of PA could be mediated by its antioxidant activity and cytoprotection of gastric mucosa.