Title: Structural basis for the substrate specificity of an S-formylglutathione hydrolase derived from Variovorax sp. PAMC 28711 Hwang J, Kim B, Lee MJ, Nam Y, Youn UJ, Lee CS, Oh TJ, Park HH, Do H, Lee JH Ref: Biochemical & Biophysical Research Communications, 629:159, 2022 : PubMed
S-Formylglutathione hydrolase was originally known to catalyze the hydrolysis of S-formylglutathione to formate and glutathione. However, this enzyme has a broader esterase activity toward substrates containing thioester and ester bonds. In a previous study, we identified a new S-formylglutathione hydrolase (VaSFGH) gene in the Antarctic bacterium Variovorax sp. PAMC 28711, and recombinant VaSFGH protein was purified and characterized. Previous enzyme activity assays showed that VaSFGH has high activity, especially toward short-chain p-nitrophenyl esters (C2-C4). In this study, we determined the crystal structure of substrate-free VaSFGH at a resolution of 2.38 A. In addition, p-nitrophenyl ester-bound VaSFGH structure models were generated by molecular docking simulations to obtain structural evidence of its substrate specificity. Comparative structural analysis of the apo-form and p-nitrophenyl ester-bound VaSFGH model structures revealed that large substrates could not bind inside the hydrophobic substrate-binding pocket because of the intrinsically static and relatively small substrate-binding pocket size of VaSFGH. This study provides useful information for further protein engineering of SFGHs for industrial use.
Title: One-year mortality among hospital survivors of cholinesterase inhibitor poisoning based on Taiwan National Health Insurance Research Database from 2003 to 2012 Chuang MC, Chang CH, Lee CS, Li SH, Hsiao CC, Fang YF, Hsieh MJ Ref: BMC Pharmacol Toxicol, 19:72, 2018 : PubMed
BACKGROUND: Acute cholinesterase inhibitor (CI) poisoning, including organophosphate and carbamate poisoning, is a crucial problem in developing countries. Acute intoxication results in a cholinergic crisis, neurological symptoms, or respiratory failure. However, the short-term and long-term outcomes of CI poisoning are seldom reported. METHODS: Data from the National Health Insurance Research Database were used to investigate the outcomes after organophosphate and carbamate poisoning. Patients who were hospitalized for a first episode of acute CI poisoning between 2003 and 2012 were enrolled in this study. Outcomes of acute CI poisoning with or without mechanical ventilation were analyzed. RESULTS: Among 6832 patients with CI poisoning, 2010 developed respiratory failure requiring mechanical ventilation, and the other 4822 patients did not require mechanical ventilation. The hospital mortality rate was higher in patients requiring mechanical ventilation than in those not requiring mechanical ventilation (33.3% versus 4.7%, p < 0.0001). In patients with respiratory failure with mechanical ventilation, the patients without pneumonia had higher mortality rate than those with pneumonia. (36.0% versus 19.9%, p < 0.0001). The 1-year mortality rate the survivors of CI poisoning was 6.7%. Among 5932 survivors after cholinesterase inhibitor poisoning, the one-year mortality rate in patients with mechanical ventilation during hospitalization was higher than those without mechanical ventilation during hospitalization (11.4% versus 5.4% respectively, p < 0.0001). CONCLUSIONS: The one-year mortality rate of survivors after CI poisoning was 6.7%. Meanwhile, age, pneumonia, and mechanical ventilation may be predictive factors for the one-year mortality among the survivors after CI poisoning. Diabetes mellitus was not a risk factor for hospital mortality in patients with CI poisoning.
Organophosphates are powerful inhibitors of acetylcholinesterase, which is critical to nerve function. Despite continuous research for detecting the highly toxic organophosphates, a new and improved methodology is still needed. Herein we demonstrate simple-to-fabricate chemiresistive gas sensors using conducting-polymer polypyrrole (PPy) nanotube transducers, which are chemically specific and capable of recognizing sub-ppb concentrations (ca. 0.5 ppb) of dimethyl methylphosphonate (DMMP), a simulant of nerve agent sarin. Interestingly, the introduction of carboxylic groups on the surface of PPy nanotube transistors resulted in enhanced sensitivity to DMMP via intermolecular hydrogen bonding. Furthermore, it was found that the sensitivity of the nanotube transducer depended on the degree of the carboxylic group introduced. Finally, a sensor array composed of 5 different transducers including the carboxylated nanotubes exhibited excellent selectivity to DMMP in 16 vapor species.
A Gram-stain-negative, non-motile, deep yellow, rod-shaped bacterium, designated strain LCS9T, was isolated from a soil sample at the tropical zone within the Ecorium of the National Institute of Ecology in Seocheon, central-western Korea. 16S rRNA gene sequence analysis showed that strain LCS9T clustered with members of the genus Flavisolibacter of the family Chitinophagaceae, phylum Bacteroidetes. Sequence similarities between strain LCS9T and the type strains of the genus Flavisolibacter ranged from 94.6 to 94.9 %. Strain LCS9T grew at 10-37 degrees C (optimum, 25 degrees C) and at pH 6.0-10.0 (optimum, pH 7); was positive for catalase and oxidase; and negative for nitrate reduction and production of indole. Cells showed pigment absorbance peaks at 451 and 479 nm, and had 0.03 % survival following exposure to 3 kGy gamma radiation. Strain LCS9T had the following chemotaxonomic characteristics: the major quinone was menaquinone-7 (MK-7); the major fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH; polar lipids included phosphoatidylethanolamine, an unidentified aminophospholipid, unidentified aminolipidsand unidentified lipids. The DNA G+C content was 39.4 mol%. Based on polyphasic analysis, the type strain LCS9T (=KCTC 42070T=JCM 19972T) represents a novel species for which the name Flavisolibacter tropicus sp. nov. is proposed. Radiation resistance in the genus Flavisolibacter has not been reported to date, and so this is the first report of low-level radiation resistance of a member of the genus.
N-myc downstream regulated gene 1 (NDRG1) has been well characterised to act as a metastatic suppressor in a number of human cancers. It has also been implicated to have a significant function in a number of physiological processes such as cellular differentiation and cell cycle. In this review, we discuss the role of NDRG1 in cancer pathology. NDRG1 was observed to be downregulated in the majority of cancers. Moreover, the expression of NDRG1 was found to be significantly lower in neoplastic tissues as compared with normal tissues. The most important function of NDRG1 in inhibiting tumour progression is associated with its ability to suppress metastasis. However, it has also been shown to have important effects on other stages of cancer progression (primary tumour growth and angiogenesis). Recently, novel iron chelators with selective antitumour activity (ie, Dp44mT, DpC) were shown to upregulate NDRG1 in cancer cells. Moreover, Dp44mT showed its antimetastatic potential only in cells expressing NDRG1, making this protein an important therapeutic target for cancer chemotherapy. This observation has led to increased interest in the examination of these novel anticancer agents.
The dipeptidyl peptidase IV (DPIV) enzyme family contains both potential and proven therapeutic targets. Recent reports indicate the presence of DP8 and DP9 in peripheral blood lymphocytes, testis, lung, and brain. For a more comprehensive understanding of DP8 and DP9 tissue and cellular expression, mRNA and enzyme activity were examined. Many organs from C57BL/6 wild-type and DPIV gene-knockout mice were examined; DP8/9 enzyme activity was detected in the immune system, brain, testis, muscle, and epithelia. In situ hybridization localized DP8 and DP9 mRNA to lymphocytes and epithelial cells in liver, gastrointestinal tract, lymph node, spleen, and lung. DP8 and DP9 mRNA was detected in baboon and mouse testis, and DP9 expression was elevated in human testicular cancers. DP8 and DP9 mRNA were ubiquitous in day 17 mouse embryo, with greatest expression in epithelium (skin and gastrointestinal tract) and brain. Thus, DP8 and DP9 are widely expressed enzymes. Their expression in lymphocytes and epithelia indicates potential for roles in the digestive and immune systems. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
Synthesis of a novel series of DPPIV inhibitors with 1,2,4- and 1,3,4-oxadiazolyl ketone derivatives and its structure-activity relationships are discussed. Compound 18h showed good inhibitory activity against DPPIV and favorable pharmacokinetic properties. In vivo pharmacodynamic efficacy and co-crystal structure of compound 18h with DPPIV is also described.
Circulating antiplasmin-cleaving enzyme (APCE) has a role in fibrinolysis and appears structurally similar to fibroblast activation protein (FAP), a cell-surface proteinase that promotes invasiveness of certain epithelial cancers. To explore this potential relationship, we performed comparative structure/function analyses of the 2 enzymes. APCE from human plasma and recombinant FAP (rFAP) exhibited identical pH optima of 7.5, extinction coefficients (in(280 nm)(1%)) of 20.2 and 20.5, common sequences of tryptic peptides, and cross-reactivity with FAP antibody. APCE and rFAP are homodimers with monomeric subunits of 97 and 93 kDa. Only homodimers appear to have enzymatic activity, with essentially identical kinetics toward Met-alpha2-antiplasmin (Met-alpha2AP) and peptide substrates. APCE and rFAP cleave both Pro3-Leu4 and Pro12-Asn13 bonds of Met-alpha2AP, but relative kcat/Km values for Pro12-Asn13 are about 16-fold higher than for Pro3-Leu4. APCE and rFAP demonstrate higher kcat/Km values toward a peptide modeled on P4-P4' sequence surrounding the Pro12-Asn13 primary cleavage site than for Z-Gly-Pro-AMC and Ala-Pro-AFC substrates. These data support APCE as a soluble derivative of FAP and Met-alpha2AP as its physiologic substrate. Conversion of Met-alpha2AP by membrane or soluble FAP to the more easily fibrin-incorporable form, Asn-alpha2AP, may increase plasmin inhibition within fibrin surrounding certain neoplasms and have an impact on growth and therapeutic susceptibility.
Initial toxicity testing of neostigmine for intrathecal (IT) injection was performed with preservative-free isobaric solution, yet currently available formulations contain the preservatives methyl- and propylparaben and are usually mixed with glucose to yield hyperbaric solutions. Since it has been proposed that preservatives and hyperbaricity increase the risk of neurotoxicity after IT injection, we examined the safety of chronically administered IT neostigmine containing these additives in sheep and rats. Rats receiving daily IT injections of glucose alone or of glucose with preservative-containing neostigmine, 5 and 10 microg, exhibited dose-related antinociception, tremor, and rigidity. In comparison to our previously published study of neostigmine injection in solution without glucose, rats receiving IT neostigmine with glucose displayed less rigidity, tremor, and salivation. Sheep receiving daily injection of glucose alone or with preservative-containing neostigmine, 1 mg, for 14 days exhibited no histologic evidence of neurotoxicity, nor did they exhibit abnormalities in cerebrospinal fluid chemistry aside from those caused by inflammation. Spinal cord histologic examination in both species revealed fibrosis and inflammation secondary to the catheter without evidence of neuronal damage. These studies support the safety of paraben- and glucose-containing IT neostigmine.
