Yong Cui

Shenyang Pharmaceutical University, Feng-t’ien, Liaoning, China

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Publications (12)24.6 Total impact

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    ABSTRACT: Elucidating structural determinants in the functional regions of toxins can provide useful knowledge for designing novel analgesic peptides. A series of 100 ns MD simulations were performed on the scorpion toxin BmK AGAP in native and disulphide bond broken states. The comparison of disulphide bond broken states with the native state showed the α-helix was found to be the key to the analgesic activity. Furthermore, our results revealed disulphide bonds have considerable influence on the functionally important essential modes of motions and the correlations between the motions of the Core domain and the C-terminal region which are involved in the analgesic activity. Therefore, we can conclude that disulphide bonds have a crucial role in modulating the function via adjusting the dynamics of scorpion toxin BmK AGAP molecule.
    No preview · Article · Oct 2015 · Molecular Simulation
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    ABSTRACT: Analgesic-antitumor peptide (AGAP), one of the scorpion toxin polypeptides, has been shown to have an antitumor activity. Recombinant AGAP (rAGAP) was shown to affect the migration and invasion of HepG2 cells via a voltage-gated sodium channel (VGSC) β1 subunit. The VGSC β1 subunit was validated as a cell adhesion molecule (CAM) in human hepatocellular carcinoma (HCC) cell lines. rAGAP suppresses the migration and invasion of HepG2 cells but has no significant effect of human liver HL7702 cells without β1 subunit expression. rAGAP inhibits the migration and invasion of the cells when the VGSC β1 subunit is overexpressed in HL7702 cells. To explain these findings, VGSC β1 subunit messenger RNA (mRNA) and protein levels were measured. The β1 subunit protein level was upregulated in a dose-dependent manner following treatment with rAGAP while there was no significant change in the mRNA level, so rAGAP might be an active component of the VGSC β1 subunit.
    No preview · Article · Sep 2015 · Tumor Biology
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    ABSTRACT: Scorpion venoms are complex mixtures of dozens or even hundreds of distinct proteins, many of which have diverse bioactivities. In this study, after bioassay-driven chromatographic purification, a new dual-function peptide with analgesic and antitumor activities was isolated and designated BmK AGAP-SYPU2. The first 12 amino acid residues were sequenced with Edman degradation. The cDNA was cloned by using rapid amplification of cDNA ends from the cDNA pool from scorpion glands. The amino acid sequence of BmK AGAP-SYPU2 was then deduced, and is consistent with the molecular mass measured with MALDI-TOF-MS. A preliminary pharmacological analysis revealed the following: in the dose–effect curve plotted with the mouse-twisting test, BmK AGAP-SYPU2 showed analgesic activity with an ED50 value of 1.42 mg/kg; in the time–effect curves plotted with a hot-plate procedure, BmK AGAP-SYPU2 had similar effects to those of the painkiller morphine, except for its longer duration. BmK AGAP-SYPU2 also showed antitumor activity against Ehrlich ascites tumor and S-180 fibrosarcoma models in vivo. Sequence alignment and homology modeling showed that BmK AGAP-SYPU2 is highly conserved relative to other scorpion α-toxins. However, a few different amino acids endow it with unique molecular properties, which may be responsible for its specific bioactivities. BmK AGAP-SYPU2, a new scorpion neurotoxin with dual functions, is a potential candidate drug amenable to exploitation and modification.
    No preview · Article · Jan 2013 · Peptides
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    ABSTRACT: Elucidating structural determinants in the functional regions of toxins can provide useful knowledge for designing novel analgesic peptides. Glycine residues at the C-terminal region of the neurotoxin BmK AGP-SYPU2 from the scorpion Buthus martensii Karsch (BmK) have been shown to be crucial to its analgesic activity. However, there has been no research on the structure-function relationship between the C-terminal segment of this toxin and its analgesic activity. To address this issue, we performed three MD simulations: one on the native structure and the other two on mutants of that structure. Results of these calculations suggest that the existence of glycine residues at the C-terminal segment stabilizes the protruding topology of the NC domain, which is considered an important determinant of the analgesic activity of BmK AGP-SYPU2.
    No preview · Article · Nov 2012 · Journal of Molecular Modeling
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    ABSTRACT: In this study, we investigated the functional role of arginines in the C-terminal (65-67) of BmK AGP-SYPU1, an analgesic peptide from the Chinese scorpion Buthus martensii Karsch. Using site-directed mutagenesis, arginines at the C-terminal (65-66) were deleted or added to the C-terminal (67). The genes for three mutants of BmK AGP-SYPU1 were obtained by PCR. An analgesic activity assay was used to evaluate the role of arginine residues in the analgesic activity. The three-dimensional structure of BmK AGP-SYPU1 was established by homology modeling. As a result, we showed that the arginines in the C-terminal are crucial for the analgesic activity and may be located at analgesic functional sites. Our work has implications for further modification of scorpion toxins to obtain new analgesic peptides with enhanced activity.
    No preview · Article · Aug 2012 · Applied biochemistry and biotechnology
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    ABSTRACT: In this study, a new peptide named BmK AGP-SYPU1 with an analgesic effect was purified from the venom of Chinese scorpion Buthus martensi Karsch (BmK) through a four-step chromatographic process. The mouse twisting test was used to identify the target peptides in every separation step. The purified BmK AGP-SYPU1 was further qualified by RP-HPLC and HPCE. The molecular mass determined by the MALDI-4800-TOF/TOF MS for BmK AGP-SYPU1 was 7544 Da. Its primary structure of the N-terminal was obtained using Edman degradation. The gene sequence of BmK AGP-SYPU1 was cloned from the cDNA pool and genomic of scorpion glands, respectively, and then expressed in Escherichia coli. The sequence determination showed that BmK AGP-SYPU1 was composed of 66 amino acid residues with a new primary structure. The metal chelating affinity column and cation exchange chromatography were used to purify the recombinant BmK AGP-SYPU1. Consequently, the native and recombinant BmK AGP-SYPU1 showed similar analgesic effects on mice as assayed using a mouse twisting model. These results suggested that BmK AGP-SYPU1 is a new analgesic component found in the Chinese scorpion Buthus martensi Karsch.
    No preview · Article · Jul 2011 · Biomedical Chromatography
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    ABSTRACT: The existence of glycine residues in long-chain scorpion toxins has been well documented. However, their role as analgesics has not been evaluated. To address this issue, we investigated the functional role of glycines in the C-terminal end of Chinese-scorpion toxin from Buthus martensii Karsch (BmK AGP-SYPU2) using site-directed mutagenesis and analgesic activity assays. Recombinant BmK AGP-SYPU2 and its mutants were efficiently expressed in E. coli and purified to homogeneity using immobilized metal ion affinity chromatography (IMAC) and cation exchange chromatography. The mouse-twisting test was used to detect the analgesic activity of BmK AGP-SYPU2 and its mutants. As a result, we identified glycines at the C-terminal end that, when altered, significantly affected analgesic activity. Also, Mut6566 was significantly decreased compared to BmK AGP-SYPU2. These data indicate that the glycines at the C-terminal end are important for the analgesic activity of BmK AGP-SYPU2.
    Preview · Article · Dec 2010 · BMB reports
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    ABSTRACT: This study utilized the E. coli expression system to investigate the role of amino acid residues in toxin from the Chinese scorpion--Buthus martensii Karsch (BmKAS). To evaluate the extent to which residues of the toxin core contribute to its analgesic activity, ten mutants of BmKAS were obtained by PCR. Using site-directed mutagenesis, all of these residues were substituted with different amino acids. This study represents a thorough mapping and elucidation of the epitopes that form the molecular basis of the toxin's analgesic activity. Our results showed large mutant-dependent differences that emphasize the important roles of the studied residues.
    No preview · Article · Oct 2010 · Archives of Pharmacal Research
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    ABSTRACT: The genomic DNA sequence encoding an antitumor-analgesic peptide was amplified from the genome of Chinese scorpion Buthus martensii Karsch (BmKAGAP), then cloned and sequenced. An intron, with a high A + T content (61.6%), splits a glycine codon near the end of the precursor signal peptide and the consensus GT/AG splice junction was identified in the BmKAGAP gene. Using PCR amplification, we confirmed the identity of our cloned cDNA, and found that the BmKAGAP gene contained an intron of 506 bp in length, which was almost identical to that of the characterized scorpion sodium channel ligands in size, consensus junctions, putative branch point and A + T content. This is the first report of using a statistical method for Chinese scorpion B. martensii Karsch genomic sequence analysis, involving the extraction of some putative transcription regulatory factors. Moreover, it establishes a theoretical foundation for studying the relationship between scorpion evolution, gene expression and protein function.
    No preview · Article · Apr 2010 · Toxicon
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    ABSTRACT: In this study, an effective Escherichia coli expression system was used to study the role of residues in the antitumor-analgesic peptide from Chinese scorpion Buthus martensii Karsch (BmKAGAP). To evaluate the extent to which residues of the toxin core contribute to its analgesic activity, nine mutants of BmKAGAP were obtained by PCR. Using site-directed mutagenesis, all of these residues were individually substituted by one amino acid. These were then subjected to a circular dichroism analysis, and an analgesic activity assay in mice. This study represents a thorough mapping and elucidation of the epitopes that underlie the molecular basis of the analgesic activity. The three-dimensional structure of BmKAGAP was established by homology modeling. Our results revealed large mutant-dependent differences that indicated important roles for the studied residues. With our ongoing efforts for establishing the structure and analgesic activity relationship of BmKAGAP, we have succeeded in pinpointing which residues are important for the analgesic activity.
    No preview · Article · Mar 2010 · Peptides
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    ABSTRACT: An increasing number of analgesic peptides have been found in the tail toxicyst, but there has been little research into their analgesic domains. Where are the analgesic domains in a conservative betaalphabetabeta topology conformation of the analgesic peptides? We have carried out research to address this question. On account of the importance of disulfide bonds in the study of protein structure, the conformational stability, catalytic activity and folding, and site-directed mutagenesis in disulfide bridges have been used to look for the analgesic domain in a mature antitumor-analgesic peptide from the venom of the Chinese scorpion Buthus martensii Karsch (BmK AGAP). The mouse-twisting assay was used to examine the analgesic activity of 12 mutants, in which two mutants (C22S, C46S) and (C16S, C36S), exhibited lower relative activity. Following the conformational analysis, one domain, called the "core domain", was found to be the key to the analgesic activity.
    No preview · Article · Mar 2010 · Biochemical and Biophysical Research Communications
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    ABSTRACT: BmK AGAP is a multifunction scorpion peptide from the venom of Buthus martensii Karsch (BmK). In this study, BmK AGAP was for the first time expressed in a soluble and active form in Escherichia coli (E. coli). The recombinant protein was then purified by metal chelating affinity chromatography. About 1.6 mg/L purified recombinant BmK AGAP (rBmK AGAP) could be obtained. Then, the antitumor effects of the rBmK AGAP were measured in vitro. MTT assay showed that the rBmK AGAP inhibited the growth of the human hepatoma cell line Hep3B and the human lung carcinoma cell line A549 in a dose-dependent manner. The IC 50 values were 24.3 μmol/L and 26.0 μmol/L, respectively, 24 hr after exposure to rBmK AGAP. Using photomicroscopy, it was found that rBmK AGAP could kill both Hep3B cells and A549 cells. All these results suggested that the rBmK AGAP could be potentially used in the development of anticancer drugs.
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