Construction and characterization of Cu²⁺, Ni²⁺, Zn²⁺, and Co²⁺ modified-DNA crystals.

We studied the physical characteristics of modified-DNA (M-DNA) double crossover crystals fabricated via substrate-assisted growth with various concentrations of four different divalent metallic ions, Cu(2+), Ni(2+), Zn(2+), and Co(2+). Atomic force microscopy (AFM) was used to test the stability of the M-DNA crystals with different metal ion concentrations. The AFM images show that M-DNA crystals formed without deformation at up to the critical concentrations of 6 mM of [Cu(2+)], 1.

Noble polymeric surface conjugated with zwitterionic moieties and antibodies for the isolation of exosomes from human serum.

New zwitterionic polymer-coated immunoaffinity beads were developed to resist nonspecific protein adsorption from undiluted human serum for diagnostic applications of exosomes. A zwitterionic sulfobetaine monomer with an amine functional group was employed for simple surface chemistry and antifouling properties. An exosomal biomarker protein, epithelial cell adhesion molecule (EpCAM), was selected as a target molecule in this work.

A direct extraction method for microRNAs from exosomes captured by immunoaffinity beads.

A direct extraction method was developed for exosomal microRNAs. After isolation of exosomes from human serum by immunoaffinity magnetic beads, microRNAs were extracted by just mixing beads with a lysis solution and heating without further purification. The lysis solution was composed of a nonionic detergent and salt (NaCl).

Peptide-cleaving catalyst selective for melanin-concentrating hormone: Oxidative decarboxylation of N-terminal aspartate catalyzed by Co(III)cyclen.

To provide a firm basis for the new paradigm of drug discovery based on catalysts for oxidative cleavage of N-terminal aspartate (Asp) residues of oligopeptides, oligopeptide-cleaving catalysts were searched by using melanin-concentrating hormone (MCH) as the substrate. MCH is a target for designing drugs to reduce obesity. Catalyst candidates containing the Co(III) complex of cyclen as the catalytic center were prepared by multicomponent condensation reactions.

Angiotensin-cleaving catalysts: conversion of N-terminal aspartate to pyruvate through oxidative decarboxylation catalyzed by Co(III)cyclen.

To provide a firm basis for the new paradigm of drug discovery based on peptide-cleaving catalysts, oligopeptide-cleaving catalysts were searched for by using human angiotensin I (Ang-I) and angiotensin II (Ang-II) as the substrates. Catalyst candidates containing the Co(III) complex of cyclen as the catalytic center were prepared by multicomponent condensation reactions. From two types of chemical libraries containing about 3,600 catalyst candidates, two compounds [SS-Co(III)X and S-Co(III)Y] were selected as the most active catalysts.

Peptide-cleaving catalyst selective for peptide deformylase.

A peptide-cleaving catalyst selective for peptide deformylase (PDF) was obtained from a library containing about 15 000 catalyst candidates. The catalyst cleaved the polypeptide backbone of PDF at Gln(152)-Arg(153). Docking simulations suggested multiple modes of interactions in the complex formed between the catalyst and PDF.

Effective artificial proteases synthesized by covering silica gel with aldehyde and various other organic groups.

Organic artificial proteases with broad substrate specificity were synthesized by covering the surface of silica gel with aldehyde and the functional groups present in amino acids. The artificial proteases hydrolyzed ovalbumin, albumin, hemoglobin, gamma-globulin with half-lives as short as 50 min at 25 degrees C or 7 min at 50 degrees C.

Analogues of aspartic proteases synthesized by densely covering silica gel with carboxyl groups.

Aspartic protease analogues synthesized by covering the surface of silica gel with carboxyl groups effectively hydrolyzed hemoglobin and gamma-globulin. It is proposed that the carboxyl group is involved in both complexation of the protein substrate and the catalytic cleavage of the peptide bonds of the complexed proteins.

Silica-based artificial protease exploiting aldehyde groups as catalytic elements.

An artificial protease synthesized by covering the surface of silica gel with aldehyde and indole groups effectively hydrolyzed albumin and gamma-globulin. It is proposed that the aldehyde group is involved in both complexation of the protein substrate and the catalytic cleavage of the peptide bonds of the complexed proteins.