Ligand-based design and synthesis of new trityl histamine and trityl cysteamine derivatives as SIRT2 inhibitors for cancer therapy.

The relentless pursuit of novel therapeutic agents against cancer has led to the identification of multiple molecular targets, among which Sirtuin 2 (SIRT2) has garnered significant attention. This study presents an extensive SAR study of our reported trityl scaffold-based SIRT2 inhibitors. This study encompasses a range of different medicinal chemistry approaches to improve the activity of the lead compounds TH-3 and STCY1. The rationally designed and synthesized structures were confirmed using NMR and high-resolution mass spectroscopy before performing SIRT2 inhibition assay, NCI60 cytotoxicity test, and cell cycle analysis. Indeed, our strategies afforded hitherto unreported SIRT2 inhibitors with high activity, particularly 2a, 4a, 7c, and 7f. Remarkably, the presence of a lipophilic para substitution on the phenyl group of a freely rotating or a locked trityl moiety enhanced activity SIRT2 inhibition. Concomitantly, the synthesized compounds showed prominent activity against different cancer lines from the NCI60 assay. Of interest, compound 7c stands out as a potent and highly selective antiproliferative agent against leukemia and colon cancer panels. Furthermore, 7c treatment resulted in cell cycle arrest in MCF-7 cells at G2 phase and did not cause in vitro DNA cleavage.

Ultrasound and computed tomography findings of hepatic portal venous gas associated with acute appendicitis in a paediatric patient: A case report.

Introduction: Hepatic portal venous gas is a rare and life-threatening condition characterised by the presence of gas in the portal vein. Hepatic portal venous gas is frequently associated with intestinal ischaemia and necrosis. We present the case of a paediatric patient with acute appendicitis with hepatic portal venous gas detected using ultrasonography. Case report: A 5-year-old boy was admitted to our hospital with a respiratory tract infection. The boy started vomiting on day 2 of hospitalisation. He did not complain of any symptoms due to developmental retardation. We performed bedside point-of-care ultrasound, which detected hepatic portal venous gas, although the appendix could not be detected due to an acoustic shadow associated with bowel gas. Contrast-enhanced computed tomography revealed perforated appendicitis and pneumatosis intestinalis associated with paralytic ileus. An emergency laparoscopic appendectomy was performed. He was discharged on day 25 of hospitalisation after antibiotic therapy. Discussion: The present case suggests that the mechanism of hepatic portal venous gas was paralytic ileus, which caused gas-forming bacterial proliferation. The gas produced by bacteria and/or the gas-forming bacteria entered the bowel wall, which caused pneumatosis intestinalis. The bubbles in the intestinal wall floated in the portal system and were detected as hepatic portal venous gas. Perforated appendicitis and paralytic ileus seemed to be caused by a delayed diagnosis of appendicitis. The point-of-care ultrasound examination was useful for detecting hepatic portal venous gas and for helping establish the diagnosis of appendicitis. Conclusion: Hepatic portal venous gas is a rare finding associated with appendicitis in children. In addition, point-of-care ultrasound is useful for detecting hepatic portal venous gas in paediatric patients.

HIV-1 Gag MA domain binds to cardiolipin in a binding mode distinct from virus assemble mediator PI(4,5)P2.

The human immunodeficiency virus type 1 (HIV-1) Gag protein is responsible for facilitating HIV-1 virion assembly and budding. Our study demonstrates that cardiolipin (CL), a component found in the inner mitochondrial membrane, exhibits the highest binding affinity to the N-terminal MA domain of the HIV-1 Gag protein within the lipid group of host cells. To assess this binding interaction, we synthesized short acyl chain derivatives of CL and employed surface plasmon resonance (SPR) analysis to determine the dissociation constants (Kd) for CL and the MA domain. Simultaneously, we examined the Kd of D-myo-phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 ) derivatives, known to play a crucial role in virion formation. Among all the derivatives, Tetra-C7 -CL exhibited the lowest Kd value (Kd = 30.8 ± 6.9 µM) for MA binding on the CL analog-immobilized sensorchip, indicating a higher affinity. Similarly, the Kd value of Di-C7 -PIP2 (Kd = 36.6 ± 4.7 µM) was the lowest on the PI(4,5)P2 analog-immobilized sensorchip. Thus, Tetra-C7 -CL binds to the MA domain using a distinct binding mode while displaying a comparable binding affinity to Di-C7 -PIP2. This discovery holds significant implications for comprehending the virological importance of CL-MA domain binding, such as its subcellular distribution, including mitochondrial translocation, and involvement in viral particle formation in concert with PI(4,5)P2 . Furthermore, this study has the potential to contribute to the development of drugs in the future.

An ADAM17 selective inhibitor promotes glucose uptake by activating AMPK.

AMPK activation promotes glucose and lipid metabolism. Here, we found that our previously reported ADAM17 inhibitor SN-4 activates AMPK and promotes membrane translocation and sugar uptake of GLUT4. AMPK inhibitor dorsomorphin reversed this effect of SN-4, confirming that the effect is mediated by AMPK activation. In addition, SN-4 inhibited lipid accumulation in HepG2 under high glucose conditions by promoting lipid metabolism and inhibiting lipid synthesis. Although lactic acidosis is a serious side effect of biguanides such as metformin, SN-4 did not affect lactate production. Furthermore, SN-4 was confirmed to inhibit the release of TNF-α, a causative agent of insulin resistance, from adipocytes. In diabetes treatment, it is important to not only regulate blood sugar levels but also prevent complications. Our findings reveal the therapeutic potential of SN-4 as a new antidiabetic drug that can also help prevent future complications.

Structural Characterization of TRAF6 N-Terminal for Therapeutic Uses and Computational Studies on New Derivatives.

Tumor necrosis factor receptor-associated factors (TRAFs) are a protein family with a wide variety of roles and binding partners. Among them, TRAF6, a ubiquitin ligase, possesses unique receptor binding specificity and shows diverse functions in immune system regulation, cellular signaling, central nervous system, and tumor formation. TRAF6 consists of an N-terminal Really Interesting New Gene (RING) domain, multiple zinc fingers, and a C-terminal TRAF domain. TRAF6 is an important therapeutic target for various disorders and structural studies of this protein are crucial for the development of next-generation therapeutics. Here, we presented a TRAF6 N-terminal structure determined at the Turkish light source "Turkish DeLight" to be 3.2 Å resolution at cryogenic temperature (PDB ID: 8HZ2). This structure offers insight into the domain organization and zinc-binding, which are critical for protein function. Since the RING domain and the zinc fingers are key targets for TRAF6 therapeutics, structural insights are crucial for future research. Separately, we rationally designed numerous new compounds and performed molecular docking studies using this template (PDB ID:8HZ2). According to the results, 10 new compounds formed key interactions with essential residues and zinc ion in the N-terminal region of TRAF6. Molecular dynamic (MD) simulations were performed for 300 ns to evaluate the stability of three docked complexes (compounds 256, 322, and 489). Compounds 256 and 489 was found to possess favorable bindings with TRAF6. These new compounds also showed moderate to good pharmacokinetic profiles, making them potential future drug candidates as TRAF6 inhibitors.

Harnessing Oleanolic Acid and Its Derivatives as Modulators of Metabolic Nuclear Receptors.

Nuclear receptors (NRs) constitute a superfamily of ligand-activated transcription factors with a paramount role in ubiquitous physiological functions such as metabolism, growth, and reproduction. Owing to their physiological role and druggability, NRs are deemed attractive and valid targets for medicinal chemists. Pentacyclic triterpenes (PTs) represent one of the most important phytochemical classes present in higher plants, where oleanolic acid (OA) is the most studied PTs representative owing to its multitude of biological activities against cancer, inflammation, diabetes, and liver injury. PTs possess a lipophilic skeleton that imitates the NRs endogenous ligands. Herein, we report a literature overview on the modulation of metabolic NRs by OA and its semi-synthetic derivatives, highlighting their health benefits and potential therapeutic applications. Indeed, OA exhibited varying pharmacological effects on FXR, PPAR, LXR, RXR, PXR, and ROR in a tissue-specific manner. Owing to these NRs modulation, OA showed prominent hepatoprotective properties comparable to ursodeoxycholic acid (UDCA) in a bile duct ligation mice model and antiatherosclerosis effect as simvastatin in a model of New Zealand white (NZW) rabbits. It also demonstrated a great promise in alleviating non-alcoholic steatohepatitis (NASH) and liver fibrosis, attenuated alpha-naphthol isothiocyanate (ANIT)-induced cholestatic liver injury, and controlled blood glucose levels, making it a key player in the therapy of metabolic diseases. We also compiled OA semi-synthetic derivatives and explored their synthetic pathways and pharmacological effects on NRs, showcasing their structure-activity relationship (SAR). To the best of our knowledge, this is the first review article to highlight OA activity in terms of NRs modulation.

Gypsogenin Battling for a Front Position in the Pentacyclic Triterpenes Game of Thrones on Anti-Cancer Therapy: A Critical Review-Dedicated to the Memory of Professor Hanaa M. Rady.

In the last decade, gypsogenin has attracted widespread attention from medicinal chemists by virtue of its prominent anti-cancer potential. Despite its late identification, gypsogenin has proved itself as a new anti-proliferative player battling for a frontline position among other classic pentacyclic triterpenes such as oleanolic acid, glycyrrhetinic acid, ursolic acid, betulinic acid, and celastrol. Herein, we present the most important reactions of gypsogenin via modification of its four functional groups. Furthermore, we demonstrate insights into the anti-cancer activity of gypsogenin and its semisynthetic derivatives and go further by introducing our perspective to judiciously guide the prospective rational design. The present article opens a new venue for a better exploitation of gypsogenin chemical entity as a lead compound in cancer chemotherapy. To the best of our knowledge, this is the first review article exploring the anti-cancer activity of gypsogenin derivatives.

The unique activity of saponin: Induction of cytotoxicity in HTLV-1 infected cells.

Infection with the retrovirus human T-cell leukemia virus type 1 (HTLV-1) sometimes causes diseases that are difficult to cure. To find anti-HTLV-1 natural compounds, we opted to screen using the HTLV-1-infected T-cell line, MT-2. Based on our results, an extract of the pulp/seeds of Akebia quinata Decaisne fruit killed MT-2 cells but did not affect the Jurkat cell line that was not infected with virus. To determine the active ingredients, seven saponins with one-six sugar moieties were isolated from A. quinata seeds, and their activities against the two cell lines were examined. Both cell lines were killed in a similar manner by Akebia saponins A and B. Further, Akebia saponins D, E, PK and G did not exhibit cytotoxicity. Akebia saponin C had a similar activity to the extract found in the screening. This compound was found to enhance Gag aggregation, induce the abnormal cleavage of Gag, suppress virion release, and preferentially kill HTLV-1 infected cells; however, their relationship remains elusive. Our findings may lead to the development of new therapies for infectious diseases based on the removal of whole-virus-infected cells.

New insight into the bioactivity of substituted benzimidazole derivatives: Repurposing from anti-HIV activity to cell migration inhibition targeting hnRNP M.

Drug repurposing is a distinguished approach for drug development that saves a great deal of time and money. Based on our previous successful repurposing of a compound BMMP from anti-HIV-1 therapy to anti-cancer metastatic activity, we adopted the same techniques for repurposing benzimidazole derivatives considering MM-1 as a lead compound. An extensive structure-activity relationship (SAR) study afforded three promising compounds, MM-1d, MM-1h, and MM-1j, which inhibited cell migration in a similar fashion to BMMP. These compounds suppressed CD44 mRNA expression, whereas only MM-1h further suppressed mRNA expression of the epithelial-mesenchymal transition (EMT) marker zeb 1. Using benzimidazole instead of methyl pyrimidine as in BMMP resulted in better affinity for heterogeneous nuclear ribonucleoprotein (hnRNP) M protein and higher anti-cell migration activity. In conclusion, our study identified new agents that surpass the affinity of BMMP for hnRNP M and have anti-EMT activity, which makes them worthy of future attention and optimization.

Serum soluble triggering receptor expressed on myeloid cells-2 was not altered by rTMS in patients with treatment-resistant depression.

AIM: Repetitive transcranial magnetic stimulation (rTMS) is one of the most effective and minimally invasive treatments for treatment-resistant depression (TRD). However, the mechanism underlying the therapeutic effects of rTMS in patients with TRD remains unclear. In recent years, the pathogenesis of depression has been closely associated with chronic inflammation and microglia are believed to play an important role in chronic inflammation. Triggering receptor expressed on myeloid cells-2 (TREM2) plays an important role in microglial neuroinflammatory regulation. In this study, we investigated the changes in peripheral soluble TREM2 (sTREM2) before and after rTMS treatment in patients with TRD. METHODS: Twenty-six patients with TRD were enrolled in this frequency (10 Hz) rTMS study. Depressive symptoms, cognitive function, and serum sTREM2 concentrations were measured at baseline and the end of the 6-week rTMS treatment. RESULTS: This study showed that rTMS ameliorated depressive symptoms and partially improved cognitive dysfunction in TRD. However, rTMS treatment did not alter serum sTREM2 levels. CONCLUSIONS: This is the first sTREM2 study in patients with TRD who underwent rTMS treatment. These results suggest that serum sTREM2 may not be relevant for the mechanism underlying the therapeutic effect of rTMS in patients with TRD. Future studies should confirm the present findings using a larger patient sample and a sham rTMS procedure, as well as CSF sTREM2. Furthermore, a longitudinal study should be conducted to clarify the effects of rTMS on sTREM2 levels.

New Insights into the Structural Requirements of Isatin-Derived Pro-Apoptotic Agents against Acute Myeloid Leukemia.

Searching for bioactive compounds within the huge chemical space is like trying to find a needle in a haystack. Isatin is a unique natural compound which is endowed with different bio-pertinent activities, especially in cancer therapy. Herein, we envisaged that adopting a hybrid strategy of isatin and α,ß-unsaturated ketone would afford new chemical entities with strong chemotherapeutic potential. Of interest, compounds 5b and 5g demonstrated significant antiproliferative activities against different cancer genotypes according to NCI-60 screening. Concomitantly, their IC50 against HL-60 cells were 0.38 ± 0.08 and 0.57 ± 0.05 µM, respectively, demonstrating remarkable apoptosis and moderate cell cycle arrest at G1 phase. Intriguingly, an impressive safety profile for 5b was reflected by a 37.2 times selectivity against HL-60 over PBMC from a healthy donor. This provoked us to further explore their mechanism of action by in vitro and in silico tools. Conclusively, 5b and 5g stand out as strong chemotherapeutic agents that hold clinical promise against acute myeloid leukemia.

In Vitro Cytotoxicity Evaluation of Plastoquinone Analogues against Colorectal and Breast Cancers along with In Silico Insights.

Colorectal cancer (CRC) and breast cancer are leading causes of death globally, due to significant challenges in detection and management. The late-stage diagnosis and treatment failures require the discovery of potential anticancer agents to achieve a satisfactory therapeutic effect. We have previously reported a series of plastoquinone analogues to understand their cytotoxic profile. Among these derivatives, three of them (AQ-11, AQ-12, and AQ-15) were selected by the National Cancer Institute (NCI) to evaluate their in vitro antiproliferative activity against a panel of 60 human tumor cell lines. AQ-12 exhibited significant antiproliferative activity against HCT-116 CRC and MCF-7 breast cancer cells at a single dose and further five doses. MTT assay was also performed for AQ-12 at different concentrations against these two cells, implying that AQ-12 exerted notable cytotoxicity toward HCT-116 (IC50 = 5.11 ± 2.14 µM) and MCF-7 (IC50 = 6.06 ± 3.09 µM) cells in comparison with cisplatin (IC50 = 23.68 ± 6.81 µM and 19.67 ± 5.94 µM, respectively). This compound also augmented apoptosis in HCT-116 (62.30%) and MCF-7 (64.60%) cells comparable to cisplatin (67.30% and 78.80%, respectively). Molecular docking studies showed that AQ-12 bound to DNA, forming hydrogen bonding through the quinone scaffold. In silico pharmacokinetic determinants indicated that AQ-12 demonstrated drug-likeness with a remarkable pharmacokinetic profile for future mechanistic anti-CRC and anti-breast cancer activity studies.

Design, semi-synthesis and examination of new gypsogenin derivatives against leukemia via Abl tyrosine kinase inhibition and apoptosis induction.

Chronic myelogenous leukemia (CML) is characterized by Philadelphia translocation arising from Bcr-Abl fusion gene, which encodes abnormal oncoprotein showing tyrosine kinase (TK) function. Certain mutations in kinase domain, off-target effects and resistance problems of current TK inhibitors require the discovery of novel Abl TK inhibitors. For this purpose, herein, we synthesized new gypsogenin derivatives (6a-l) and evaluated their anticancer effects towards CML cells along with healthy cell line and different leukemic cells. Among these compounds, compound 6l was found as the most active anti-leukemic agent against K562 CML cells compared to imatinib exerting less cytotoxicity towards PBMCs (healthy). This compound also revealed significant anti-leukemic effects against Jurkat cell line. Besides, compound 6l enhanced apoptosis in CML cells with 52.4 % when compared with imatinib (61.8 %) and inhibited Abl TK significantly with an IC50 value of 13.04 ± 2.48 µM in a large panel of kinases accentuating Abl TK-mediated apoptosis of compound 6l in CML cells. Molecular docking outcomes showed that compound 6l formed mainly crucial interactions in the ATP-binding cleft of Abl TK similar to that of imatinib. Ultimately, in silico pharmacokinetic evaluation of compound 6l indicated that this compound was endowed with anti-leukemic drug candidate features.

A New 1,2-Naphthoquinone Derivative with Anti-lung Cancer Activity.

1,2-Naphthoquinone (2-NQ) is a nucleophile acceptor that non-selectively makes covalent bonds with cysteine residues in various cellular proteins, and is also found in diesel exhaust, an air pollutant. This molecule has rarely been considered as a pharmacophore of bioactive compounds, in contrast to 1,4-naphthoquinone. We herein designed and synthesized a compound named N-(7,8-dioxo-7,8-dihydronaphthalen-1-yl)-2-methoxybenzamide (MBNQ), in which 2-NQ was hybridized with the nuclear factor-κB (NF-κB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) as a nucleophile acceptor. Although 50 µM MBNQ did not inhibit NF-κB signaling, 10 µM MBNQ induced cell death in the lung cancer cell line A549, which was insensitive to 2-NQ (10 µM). In contrast, MBNQ was less toxic in normal lung cells than 2-NQ. A mechanistic study showed that MBNQ mainly induced apoptosis, presumably via the activation of p38 mitogen-activated protein kinase (MAPK). Collectively, the present results demonstrate that the introduction of an appropriate substituent into 2-NQ constitutes a new biologically active entity, which will lead to the development of 2-NQ-based drugs.

Changes in the metabolites of cerebrospinal fluid induced by rTMS in treatment-resistant depression: A pilot study.

Repetitive transcranial magnetic stimulation (rTMS) improves depressive symptoms in treatment-resistant depression (TRD). This study aimed to analyze changes in cerebrospinal fluid (CSF) metabolites in patients with TRD after rTMS. Five patients with TRD were enrolled in a high frequency (10-Hz) rTMS study. The concentration of 72 CSF metabolites were measured at baseline and at the end of the 6-week rTMS treatment. rTMS significantly increased CSF niacinamide, kynurenine, and creatinine levels and significantly decreased CSF cystine levels, but not the levels of the other 68 CSF metabolites. This is the first CSF metabolomics study on patients with TRD who underwent rTMS.

Novel Inhibitor for Downstream Targeting of Transforming Growth Factor-ß Signaling to Suppress Epithelial to Mesenchymal Transition and Cell Migration.

Cancer metastasis accounts for most of the mortality associated with solid tumors. However, antimetastatic drugs are not available on the market. One of the important biological events leading to metastasis is the epithelial to mesenchymal transition (EMT) induced by cytokines, namely transforming growth-factor-ß (TGF-ß). Although several classes of inhibitors targeting TGF-ß and its receptor have been developed, they have shown profound clinical side effects. We focused on our synthetic compound, HPH-15, which has shown anti-fibrotic activity via the blockade of the TGF-ß Smad-dependent signaling. In this study, 10 µM of HPH-15 was found to exhibit anti-cell migration and anti-EMT activities in non-small-cell lung cancer (NSCLC) cells. Although higher concentrations are required, the anti-EMT activity of HPH-15 has also been observed in 3D-cultured NSCLC cells. A mechanistic study showed that HPH-15 inhibits downstream TGF-ß signaling. This downstream inhibition blocks the expression of cytokines such as TGF-ß, leading to the next cycle of Smad-dependent and -independent signaling. HPH-15 has AMPK-activation activity, but a relationship between AMPK activation and anti-EMT/cell migration was not observed. Taken together, HPH-15 may lead to the development of antimetastatic drugs with a new mechanism of action.

In Vitro and In Silico Study of Analogs of Plant Product Plastoquinone to Be Effective in Colorectal Cancer Treatment.

Plants have paved the way for the attainment of molecules with a wide-range of biological activities. However, plant products occasionally show low biological activities and/or poor pharmacokinetic properties. In that case, development of their derivatives as drugs from the plant world has been actively performed. As plant products, plastoquinones (PQs) have been of high importance in anticancer drug design and discovery; we have previously evaluated and reported the potential cytotoxic effects of a series of PQ analogs. Among these analogs, PQ2, PQ3 and PQ10 were selected for National Cancer Institute (NCI) for in vitro screening of anticancer activity against a wide range of cancer cell lines. The apparent superior anticancer potency of PQ2 on the HCT-116 colorectal cancer cell line than that of PQ3 and PQ10 compared to other tested cell lines has encouraged us to perform further mechanistic studies to enlighten the mode of anti-colorectal cancer action of PQ2. For this purpose, its apoptotic effects on the HCT-116 cell line, DNA binding capacity and several crucial pharmacokinetic properties were investigated. Initially, MTT assay was conducted for PQ2 at different concentrations against HCT-116 cells. Results indicated that PQ2 exhibited significant cytotoxicity in HCT-116 cells with an IC50 value of 4.97 ± 1.93 µM compared to cisplatin (IC50 = 26.65 ± 7.85 µM). Moreover, apoptotic effects of PQ2 on HCT-116 cells were investigated by the annexin V/ethidium homodimer III staining method and PQ2 significantly induced apoptosis in HCT-116 cells compared to cisplatin. Based on the potent DNA cleavage capacity of PQ2, molecular docking studies were conducted in the minor groove of the double helix of DNA and PQ2 presented a key hydrogen bonding through its methoxy moiety. Overall, both in vitro and in silico studies indicated that effective, orally bioavailable drug-like PQ2 attracted attention for colorectal cancer treatment. The most important point to emerge from this study is that appropriate derivatization of a plant product leads to unique biologically active compounds.

A New Series of Indeno[1,2-c]pyrazoles as EGFR TK Inhibitors for NSCLC Therapy.

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death throughout the world. Due to the shortcomings of traditional chemotherapy, targeted therapies have come into prominence for the management of NSCLC. In particular, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy has emerged as a first-line therapy for NSCLC patients with EGFR-activating mutations. In this context, new indenopyrazoles, which were prepared by an efficient microwave-assisted method, were subjected to in silico and in vitro assays to evaluate their potency as EGFR TK-targeted anti-NSCLC agents. Compound 4 was the most promising antitumor agent towards A549 human lung adenocarcinoma cells, with an IC50 value of 6.13 µM compared to erlotinib (IC50 = 19.67 µM). Based on its low cytotoxicity to peripheral blood mononuclear cells (PBMCs), it can be concluded that compound 4 exerts selective antitumor action. This compound also inhibited EGFR TK with an IC50 value of 17.58 µM compared to erlotinib (IC50 = 0.04 µM) and induced apoptosis (56.30%). Taking into account in silico and in vitro data, compound 4 stands out as a potential EGFR TKI for the treatment of NSCLC.

Development of chimeric receptor activator of nuclear factor-kappa B with glutathione S-transferase in the extracellular domain: Artificial switch in a membrane receptor.

Various chimeric receptors have been developed and used for biological experiments. In the present study, we constructed three types of chimeric receptor activator of nuclear factor-kappa B (RANK) with the glutathione S-transferase (GST) protein in the extracellular domain, and stimulated them using newly synthesized chemical trimerizers with three glutathiones. Although this stimulation did not activate these proteins, we unexpectedly found that the chimera named RANK-GST-SC, in which GST replaced a major part of the RANK extracellular domain, activated nuclear factor-kappa B (NF-κB) signaling approximately sixfold more strongly than wild-type RANK without the ligand. The dimerization of extracellular GST is considered to function as a switch outside the cell, and signal transduction then occurs. GST has been widely employed as a tag for protein purification; GST-fusion protein can be conveniently captured by glutathione-conjugated beads and easily purified from impurity. The present study is a pioneering example of the novel utility of GST and provides information for the development of new chemical biology systems.