A new MS-titration method for the non-covalent binding of protein-ligand based on the research of berberine and alpha1-acid glycoprotein was established. The major presumption of new method is that the total concentration of protein-ligand complex is approximately the same as the total concentration of acting protein if a certain extent of affinity is existed between protein and ligand, in addition, the mole amount of acting ligand is more than that of acting protein. The non-covalent binding behaviours between berberine and alpha1-acid glycoprotein was studied by using electrospray ionization ion trap mass spectrometry (ESI-ITMS) , and the results were verified by fluorescence quenching method. The results showed that the binding behaviours between berberine and alpha1-acid glycoprotein, for example, stability constant, number of binding site, type of the main binding force, were almost the same by using the new MS-titration method and fluorescence quenching method. Comparing with the reported MS-titration method, the presented MS-titration method in this paper is more simple and applicable, does not demand much for the devices, and can lead to reliable results in same cases.
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J Am Chem Soc
August 2020
Department of Chemistry, Washington University at St. Louis, St. Louis, Missouri 63130, United States.
Although knowledge of the coordination chemistry and metal-withholding function of the innate immune protein human calprotectin (hCP) has broadened in recent years, understanding of its Ca-binding properties in solution remains incomplete. In particular, the molecular basis by which Ca binding affects structure and enhances the functional properties of this remarkable transition-metal-sequestering protein has remained enigmatic. To achieve a molecular picture of how Ca binding triggers hCP oligomerization, increases protease stability, and enhances antimicrobial activity, we implemented a new integrated mass spectrometry (MS)-based approach that can be readily generalized to study other protein-metal and protein-ligand interactions.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
November 2015
Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.
Rationale: Ginsenosides are an important class of natural products extracted from ginseng that possess various important biological activities. Studies of interactions of ginsenosides with proteins are essential for comprehensive understanding of the biological activities of ginsenosides. In this study, the interactions of ginsenosides with lysozyme were investigated by electrospray ionization mass spectrometry (ESI-MS).
View Article and Find Full Text PDFAnal Chem
December 2013
Department of Chemistry and Applied Biosciences, ETH Zurich , Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland.
Electrospray ionization (ESI) is increasingly used to measure binding strengths, but it is not always clear whether the ESI process introduces artifacts. Here we propose a model monomer-dimer equilibrium system based on DNA oligonucleotides to systematically explore biomolecular self-association with the ESI-mass spectrometry (MS) titration method. The oligonucleotides are designed to be self-complementary and have the same chemical composition and mass, allowing for equal ionization probability, ion transmission, and detection efficiency in ESI-MS.
View Article and Find Full Text PDFMacromol Biosci
December 2010
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
An efficient strategy is reported to introduce methacrylamide groups on the lysine residues of a model protein (lysozyme) for immobilization and triggered release from a hydrogel network. A novel spacer unit was designed, containing a disulfide bond, such that the release of the protein can be triggered by reduction. The modified proteins were characterized by MALDI-TOF MS, titration of free NH(2) residues and spectral analysis.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
August 2010
Laser Chemistry Institute, Chemistry Department, Fudan University, Shanghai 200433, China.
The non-covalent complexes of alpha- and beta-cyclodextrins (alpha-, beta-CDs) with two aryl alkanol piperazine derivatives (Pipe I and Pipe II) have been studied by electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. The ESI-MS experimental results demonstrated that Pipe I can conjugate to beta-CD and form 1:1 or 1:2 stoichiometric non-covalent complexes, and Pipe II can only form 1:1 complexes with alpha- or beta-CD. Fluorescence spectra indicated that the fluorescence intensities of Pipe I and Pipe II can be enhanced by increasing the content of beta-CD.
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