Neoechinulin A is an indole alkaloid with several biological activities. We previously reported that this compound protects neuronal PC12 cells from cytotoxicity induced by the peroxynitrite generator 3-morpholinosydnonimine (SIN-1), but the target proteins and precise mechanism of action of neoechinulin A were unclear. Here, we employed a phage display screen to identify proteins that bind directly with neoechinulin A. Our findings identified two proteins, chromogranin B and glutaredoxin 3, as candidate target binding partners for the alkaloid. QCM analyses revealed that neoechinulin A displays high affinity for both chromogranin B and glutaredoxin 3. RNA interference-mediated depletion of chromogranin B decreased the sensitivity of PC12 cells against SIN-1. Our results suggested chromogranin B is a plausible target of neoechinulin A. 相似文献
The β-amyloid (Aβ) plaque is one of the neuropathological hallmarks in the Alzheimer’s disease brain. The detection of Aβ plaques with fluorescence probes is useful for preclinical studies of Alzheimer’s disease. In this study, we developed four novel fluorescence probes based on chalcone scaffold. In an in vitro binding study, all FCH derivatives showed moderate binding affinity for Aβ(1–42) aggregates (Ki?=?72–114?nM). The fluorescence intensities of FCH-3 and FCH-4 dramatically changed in the presence of Aβ(1–42) aggregates (6.7 and 14.2 fold), but the changes of FCH-1 and FCH-2 were minor (2.0 and 2.4 fold). In a fluorescence staining study using Tg2576 mouse brain sections, FCH-3 and FCH-4 clearly visualized Aβ plaques, but FCH-1 and FCH-2 did not stain. Taken together, all FCH derivatives could bind to Aβ aggregates, but only FCH-3 and FCH-4 may be useful fluorescence probes for in vitro staining of Aβ plaques. 相似文献
We describe a medicinal chemistry approach to the discovery of a novel EP1 antagonist exhibiting high potency and good pharmacokinetics. Our starting point is 1, an EP1 receptor antagonist that exhibits pharmacological efficacy in cystometry models following intravenous administration. Despite its good potency in vitro, the high lipophilicity of 1 is a concern in long-term in vivo studies. Further medicinal chemistry efforts identified 4 as an improved lead compound with good in vitro ADME profile applicable to long term in vivo studies. A rat fracture study was conducted with 4 for 4?weeks to validate its utility in bone fracture healing. The results suggest that this EP1 receptor antagonist stimulates callus formation and thus 4 has potential for enhancing fracture healing. 相似文献
Arthrobacter sp. strain KI72 grows on a 6-aminohexanoate oligomer, which is a by-product of nylon-6 manufacturing, as a sole source of carbon and nitrogen. We cloned the two genes, nylD1 and nylE1, responsible for 6-aminohexanoate metabolism on the basis of the draft genomic DNA sequence of strain KI72. We amplified the DNA fragments that encode these genes by polymerase chain reaction using a synthetic primer DNA homologous to the 4-aminobutyrate metabolic enzymes. We inserted the amplified DNA fragments into the expression vector pColdI in Escherichia coli, purified the His-tagged enzymes to homogeneity, and performed biochemical studies. We confirmed that 6-aminohexanoate aminotransferase (NylD1) catalyzes the reaction of 6-aminohexanoate to adipate semialdehyde using α-ketoglutarate, pyruvate, and glyoxylate as amino acceptors, generating glutamate, alanine, and glycine, respectively. The reaction requires pyridoxal phosphate (PLP) as a cofactor. For further metabolism, adipate semialdehyde dehydrogenase (NylE1) catalyzes the oxidative reaction of adipate semialdehyde to adipate using NADP+ as a cofactor. Phylogenic analysis revealed that NylD1 should be placed in a branch of the PLP-dependent aminotransferase sub III, while NylE1 should be in a branch of the aldehyde dehydrogenase superfamily. In addition, we established a NylD1/NylE1 coupled system to quantify the aminotransferase activity and to enable the conversion of 6-aminohexaoate to adipate via adipate semialdehyde with a yield of > 90%. In the present study, we demonstrate that 6-aminohexanoate produced from polymeric nylon-6 and nylon oligomers (i.e., a mixture of 6-aminohexaoate oligomers) by nylon hydrolase (NylC) and 6-aminohexanoate dimer hydrolase (NylB) reactions are sequentially converted to adipate by metabolic engineering technology.
Glycosidases are used in the food, chemical, and energy industries. These proteins are some of the most frequently used such enzymes, and their thermostability is essential for long-term and/or repeated use. In addition to thermostability, modification of the substrate selectivity and improvement of the glycosidase activities are also important. Thermostabilization of enzymes can be performed by directed evolution via random mutagenesis or by rational design via site-directed mutagenesis; each approach has advantages and disadvantages. In this paper, we introduce thermostabilization of glycoside hydrolases by rational protein design using site-directed mutagenesis along with X-ray crystallography and simulation modeling. We focus on the methods of thermostabilization of glycoside hydrolases by linking the N- and C-terminal ends, introducing disulfide bridges, and optimizing β-turn structures to promote hydrophobic interactions.
Rose cultivars with blue flower color are among the most attractive breeding targets in floriculture. However, they are difficult to produce due to the low efficiency of transformation systems, interactive effects of hosts and vectors, and lengthy processes. In this study, agroinfiltration-mediated transient expression was investigated as a tool to assess the function of flower color genes and to determine appropriate host cultivars for stable transformation in Rosa hybrida. To induce delphinidin accumulation and consequently to produce blue hue, the petals of 30 rose cultivars were infiltrated with three different expression vectors namely pBIH-35S-CcF3′5′H, pBIH-35S-Del2 and pBIH-35S-Del8, harbouring different sets of flower color genes. The results obtained showed that the ectopic expression of the genes was only detected in three cultivars with dark pink petals (i.e. ‘Purple power’, ‘High & Mora’ and ‘Marina’) after 6–8 days. The high performance liquid chromatography analyses confirmed delphinidin accumulation in the infiltrated petals caused by transient expression of CcF3′5′H gene. Moreover, there were significant differences in the amounts of delphinidin among the three cultivars infiltrated with the three different expression vectors. More specifically, the highest delphinidin content was detected in the cultivar ‘Purple power’ (4.67 µg g?1 FW), infiltrated with the pBIH-35S-Del2 vector. The expression of CcF3′5′H gene in the infiltrated petals was also confirmed by real time PCR. In conclusion and based on the findings of the present study, the agroinfiltration could be regarded as a reliable method to identify suitable rose cultivars in blue rose flower production programs. 相似文献
In the amyloid cascade hypothesis, β-amyloid (Aβ) plaques is one of the major pathological biomarkers in the Alzheimer’s disease (AD) brain. We report the synthesis and evaluation of novel radiofluorinated chalcones, [18F]4-dimethylamino-4′-fluoro-chalcone ([18F]DMFC) and [18F]4′-fluoro-4-methylamino-chalcone ([18F]FMC), as Aβ imaging probes. The conversion of iodine directly introduced to the chalcone backbone into fluorine was successfully carried out by 18F-labeling via the corresponding boronate precursors, achieving the direct introduction of fluorine-18 into the chalcone backbone to prepare [18F]DMFC and [18F]FMC. In a biodistribution study using normal mice, [18F]DMFC and [18F]FMC showed a higher initial uptake (4.43 and 5.47% ID/g at 2?min postinjection, respectively) into and more rapid clearance (0.52 and 0.66% ID/g at 30?min postinjection, respectively) from the brain than a Food and Drug Administration (FDA)-approved Aβ imaging agent ([18F]Florbetapir), meaning the improvement of the probability of detecting Aβ plaques and the reduction of non-specific binding in the brain. In the in vitro binding studies using aggregates of recombinant Aβ peptides, [18F]DMFC and [18F]FMC showed high binding affinity to recombinant Aβ aggregates at the Kd values of 4.47 and 6.50?nM, respectively. In the in vitro autoradiography (ARG) experiment with AD brain sections, [18F]DMFC and [18F]FMC markedly accumulated only in a region with abundant Aβ plaques, indicating that they clearly recognized human Aβ plaques in vitro. These encouraging results suggest that [18F]DMFC and [18F]FMC may be promising PET probes for the detection of an amyloid pathology and the early diagnosis of AD with marked accuracy. 相似文献
Sleep and Biological Rhythms - Appropriate warming of the periocular or posterior cervical skin has been reported to induce autonomic or mental relaxation in humans. To clarify the effects of... 相似文献