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The celB gene of Caldicellulosiruptor saccharolyticus was cloned and expressed in Escherichia coli to create a recombinant biocatalyst for hydrolyzing lignocellulosic biomass at high temperature. The GH5 domain of CelB hydrolyzed 4-nitrophenyl-β-D-cellobioside and carboxymethyl cellulose with optimum activity at pH 4.7-5.5 and 80°C. The recombinant GH5 and(More)
BACKGROUND We have studied the effects of the poly(ethylene glycol) (PEG) chain length and acyl chain composition on the pH-sensitivity of acid-labile PEG-diorthoester (POD) lipids. The optimal conditions are described for preparation of DNA plasmid encapsulated POD nanolipoparticles (NLPs) which mediate high gene delivery activity in vitro with moderate(More)
Extreme makeover of cholesterol: Cholesterol exchange is a major reason for the instability of liposomes in blood. The formation of a covalent hybrid between cholesterol and glycerophosphocholine preserves the bilayer-stabilizing effect of free cholesterol but prevents its transfer from the bilayer. Thus, disterolphospholipids (e.g. 1) are valuable new(More)
High-affinity nitrilotriacetic acids (NTA) have great potential in the molecular manipulation of His-tagged proteins. We have developed a facile method to synthesize multivalent NTA and its conjugates. Starting with appropriately protected lysine, we synthesized the mono-NTA synthons functionalized with either an amino group or a carboxylic group. We then(More)
Retinoic acid (RA), the bioactive metabolite of retinol, is essential for robust humoral immunity in animals and humans. Recent interest in RA as a vaccine adjuvant has been encouraged by reports showing cooperative enhancement of antibody responses to tetanus toxin in rodents by all-trans RA (ATRA) and a Toll-like receptor-3 agonist. We hypothesized that(More)
Matrix attachment therapy (MAT) is an enzyme prodrug strategy that targets hyaluronan in the tumor extracellular matrix to deliver a prodrug converting enzyme near the tumor cells. A recombinant fusion protein containing the hyaluronan binding domain of TSG-6 (Link) and yeast cytosine deaminase (CD) with an N-terminal His(x6) tag was constructed to test MAT(More)
Nitrilotriacetic acid (NTA) has moderate affinity (10 μM) for hexahistidine (His6) and is widely used in the purification of His6-tagged proteins. The affinity can be increased significantly (10 nM) through multivalency such as using a tris-NTA. We show that the binding affinity of tris-NTA is dependent on the flexibility and length of the spacer between(More)
We evaluated gene transfer using PEGylated bioresponsive nanolipid particles (NLPs) containing plasmid DNA administered by convection-enhanced delivery (CED) into orthotopically implanted U87-MG tumors in rat brain. We hypothesized that attachment of the human immunodeficiency virus trans-acting transcriptional activator peptide (TATp) to pH-sensitive,(More)
Metal chelation-ligand interactions, such as occur between nitrilotriacetic acid (NTA)-nickel and multihistidines, enable the noncovalent attachment of histidine-modified proteins to liposomes and other particles. We compared three lipids: a mono-NTA lipid (ca. 10 microM affinity) and two tris-NTA lipid derivatives (ca. 3 nM and 0.2 nM affinity) in their(More)
1,2-Di-stigma-steryl-hemi-succinoyl-sn-glycero-3-phosphocholine (DSHemsPC) is a new lipid in which two molecules of stigmasterol (an inexpensive plant sterol) are covalently linked via a succinic acid to glycerophosphocholine. Since amphotericin B (AmB) interacts with sterols, we postulated that DSHemsPC could be used in AmB liposome formulations.(More)