1.Structure-Activity Relationships of JMV4463, a Vectorized Cathepsin D Inhibitor with Antiproliferative Properties: The Unique Role of the AMPA-Based Vector.
Vezenkov LL1, Sanchez CA1, Bellet V1, Martin V1, Maynadier M1, Bettache N1, Lisowski V1, Martinez J1, Garcia M1, Amblard M1, Hernandez JF2. ChemMedChem. 2016 Feb;11(3):302-8. doi: 10.1002/cmdc.201500457. Epub 2015 Dec 7.
Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their growth, the mechanism of which is still not understood. In this context, the pepstatin bioconjugate JMV4463 [Ac-arg-O2 Oc-(Val)3 -Sta-Ala-Sta-(AMPA)4 -NH2 ; O2 Oc=8-amino-3,6-dioxaoctanoyl, Sta=statine, AMPA=ortho-aminomethylphenylacetyl], containing a new kind of cell-penetrating vector, was previously shown to exhibit potent antiproliferative effects in vitro and to delay the onset of tumors in vivo. In this study, we performed a structure-activity relationship analysis to evaluate the significance of the inhibitor and vector moieties of JMV4463. By modifying both statine residues of pepstatin we found that the antiproliferative activity is correlated with CathD inhibition, supporting a major role of the catalytic activity of intracellular CathD in cancer cell proliferation. Replacing the vector composed of four AMPA units with other vectors was found to abolish cytotoxicity, although all of the conjugates enabled pepstatin transport into cells.
2.hνSABR: Photochemical Dose-Response Bead Screening in Droplets.
Price AK1, MacConnell AB1, Paegel BM1. Anal Chem. 2016 Mar 1;88(5):2904-11. doi: 10.1021/acs.analchem.5b04811. Epub 2016 Feb 13.
With the potential for each droplet to act as a unique reaction vessel, droplet microfluidics is a powerful tool for high-throughput discovery. Any attempt at compound screening miniaturization must address the significant scaling inefficiencies associated with library handling and distribution. Eschewing microplate-based compound collections for one-bead-one-compound (OBOC) combinatorial libraries, we have developed hνSABR (Light-Induced and -Graduated High-Throughput Screening After Bead Release), a microfluidic architecture that integrates a suspension hopper for compound library bead introduction, droplet generation, microfabricated waveguides to deliver UV light to the droplet flow for photochemical compound dosing, incubation, and laser-induced fluorescence for assay readout. Avobenzone-doped PDMS (0.6% w/w) patterning confines UV exposure to the desired illumination region, generating intradroplet compound concentrations (>10 μM) that are reproducible between devices.
3.Biochemical characterization of plasmepsin V from Plasmodium vivax Thailand isolates: Substrate specificity and enzyme inhibition.
Sappakhaw K1, Takasila R1, Sittikul P1, Wattana-Amorn P2, Assavalapsakul W3, Boonyalai N4. Mol Biochem Parasitol. 2015 Dec;204(2):51-63. doi: 10.1016/j.molbiopara.2016.01.003. Epub 2016 Jan 12.
Plasmepsin V (PMV) is a Plasmodium aspartic protease responsible for the cleavage of the Plasmodium export element (PEXEL) motif, which is an essential step for export of PEXEL containing proteins and crucial for parasite viability. Here we describe the genetic polymorphism of Plasmodium vivax PMV (PvPMV) Thailand isolates, followed by cloning, expression, purification and characterization of PvPMV-Thai, presenting the pro- and mature-form of PvPMV-Thai. With our refolding and purification method, approximately 1mg of PvPMV-Thai was obtained from 1g of washed inclusion bodies. Unlike PvPMV-Ind and PvPMV-Sal-1, PvPMV-Thai contains a four-amino acid insertion (SVSE) at residues 246-249. We have confirmed that this insertion did not interfere with the catalytic activity as it is located in the long loop (R241-E272) pointing away from the substrate-binding pocket. PvPMV-Thai exhibited similar activity to PfPMV counterparts in which PfEMP2 could be hydrolyzed more efficiently than HRPII.
4.Isolation and characterization of a serine protease-producing marine bacterium Marinomonas arctica PT-1.
Yoo AY1, Park JK2. Bioprocess Biosyst Eng. 2016 Feb;39(2):307-14. doi: 10.1007/s00449-015-1514-4. Epub 2015 Dec 1.
A serine protease-producing marine bacterial strain named as PT-1 was isolated and identified as a family of Marinomonas arctica, based on molecular characterization of 16S rRNA gene sequence, phylogenetic tree, and fatty acid composition analyses. Optimized culture conditions for growth of the bacterium PT-1 and production of protease (ProA) were determined to be pH 8.0 in the presence of 5 % NaCl, at 37 °C during 24 h of incubation in the presence of 1.0 % skim milk. The molecular weight of the purified ProA was estimated to be 63-kDa as a major band by SDS-PAGE. We were intrigued to find that the activity of ProA was not inhibited by pepstatin A, chymostatin, and leupeptin known as inhibitors for cysteine protease. However, phenylmethylsulfonyl fluoride (PMSF) completely inhibited protease activity, suggesting that the ProA is like a serine protease. To the best of our knowledge, this is the first report on serine protease of Marinomonas species.