N-[1-Aryl-2-(1-imidazolo)ethyl]-guanidine derivatives as potent inhibitors of the bovine mitochondrial F1F0 ATP hydrolase

A series of substituted guanidine derivatives were prepared and evaluated as potent and selective inhibitors of mitochondrial F(1)F(0) ATP hydrolase. The initial thiourethane derived lead molecules possessed intriguing in vitro pharmacological profiles, though contained moieties considered non-drug-like. Analogue synthesis efforts led to compounds with maintained potency and superior physical properties. Small molecules in this series which potently and selectivity inhibit ATP hydrolase and not ATP synthase may have utility as cardioprotective agents.     

Synthesis and activity of 1-aryl-1'-imidazolyl methyl ethers as non-thiol farnesyltransferase inhibitors

A series of imidazole-containing methyl ethers (4-5) have been designed and synthesized as potent and selective farnesyltransferase inhibitors (FTIs) by transposition of the D-ring to the methyl group on the imidazole of the previously reported FTIs 3. Several compounds such as 4h and 5b demonstrate superior enzymatic activity to the current benchmark compound tipifarnib (1) with IC(50) values in the lower subnanomolar range, while maintaining excellent cellular activity comparable to tipifarnib. The compounds are characterized as being simple, easier to make, and possess no chiral center involved.     

Design, synthesis, and activity of 4-quinolone and pyridone compounds as nonthiol-containing farnesyltransferase inhibitors

As a part of our efforts to identify potent inhibitors of farnesyltransferase (FTase), modification of the structure of tipifarnib through structure-based design was undertaken by replacing the 2-quinolones with 4-quinolones and pyridones, and subsequent relocation of the D-ring to the N-methyl group on the imidazole ring. This study has yielded a novel series of potent and selective FTase inhibitors. The X-ray structure of tipifarnib (1) in complex with FTase was described.     

Triaryl methane derivatives as antiproliferative agents

Clotrimazole (CLT) 1, a synthetic anti-fungal imidazole derivative, inhibits tumor cell proliferation and angiogenesis. In the current study, flow cytometric analysis demonstrated that the decrease in tumor cell growth by CLT 1 was associated with inhibition of cell cycle progression at the G(1)-S phase transition, resulting in G(0)-G(1) arrest. A series of CLT 1 analogues has been generated in order to develop CLT 1 derivatives that are devoid of the imidazole moiety which is responsible for the hepatoxicity associated with CLT 1 while retaining CLT 1 efficacy. The majority of these analogues demonstrate in vitro antiproliferative activity ranging from submicromolar to micromolar concentrations.     

Synthesis and biological evaluation of taxinine analogues as orally active multidrug resistance reversal agents in cancer

Three novel taxinine analogues were prepared and tested for their activity as multidrug resistance (MDR) reversal agents in comparison with verapamil. In vitro testing demonstrated that compounds 8-10 possess MDR-reversal activity in the KB/V cell line. Half-hour after treatment with 5, 10, and 20 micromol/L compound 9, the intracellular rhodamine123 concentration increased 2.3, 2.9, and 3.2-fold, respectively, higher than 1.88-fold of 10 micromol/L verapamil in KB/V cell line. In vivo studies with VCR-resistant KB/V tumor xenografts showed that compound 9 in combination with VCR significantly inhibited tumor growth. Treatment with VCR or 9 alone did not result in growth inhibition. These results reveal that three taxinine analogues are good modifiers of MDR in tumor cells.     

Insights into the structure, mechanism, and regulation of scavenger mRNA decapping activity

Complete removal of residual N-7 guanine cap from degraded messenger RNA is necessary to prevent accumulation of intermediates that might interfere with RNA processing, export, and translation. The human scavenger decapping enzyme, DcpS, catalyzes residual cap hydrolysis following mRNA degradation, releasing N-7 methyl guanosine monophosphate and 5'-diphosphate terminated cap or mRNA products. DcpS structures bound to m(7)GpppG or m(7)GpppA reveal an asymmetric DcpS dimer that simultaneously creates an open nonproductive DcpS-cap complex and a closed productive DcpS-cap complex that alternate via 30 A domain movements. Structural and biochemical analysis suggests an autoregulatory mechanism whereby premature decapping mRNA is prevented by blocking the conformational changes that are required to form a closed productive active site capable of cap hydrolysis.     

Purification of filamentous bacteriophage M13 by expanded bed anion exchange chromatography

In this paper, we investigated the development of a simplified and rapid primary capture step for the recovery of M13 bacteriophage from particulate-containing feedstock. M13 bacteriophage, carrying an insert, was propagated and subsequently purified by the application of both conventional multiple steps and expanded bed anion exchange chromatography. In the conventional method, precipitation was conducted with PEG/NaCl, and centrifugation was also performed. In the single step expanded bed anion exchange adsorption, UpFront FastLine 20 (20 mm i.d.) from UpFront Chromatography was used as the contactor, while 54 ml (Ho = 15 cm) of STREAMLINE DEAE (rho = 1.2 g/cm3) from Amersham Pharmacia Biotechnology was used as the anion exchanger. The performance of the two methods were evaluated, analysed, and compared. It was demonstrated that the purification of the M13 bacteriophage, using expanded bed anion exchange adsorption, yielded the higher recovery percentage, at 82.86%. The conventional multiple step method yielded the lower recovery percentage, 36.07%. The generic application of this integrated technique has also been assessed.     

Optimal conditions for hepatitis B core antigen production in shaked flask fermentation

The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed (150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production ofEscherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at PH 7, 37°C and at a rotational speed of 250 rpm which is 0.927 h⁻¹. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the highest growth rate (0.927 h⁻¹) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C. The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of the protein yield for theE. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher compared to the lowest yield achieved, at 30°C.     

Cloning, characterization and expression of CDK5RAP1_v3 and CDK5RAP1_v4, two novel splice variants of human CDK5RAP1

Two novel splice variants of CDK5RAP1, named CDK5RAP1_v3 and CDK5RAP1_v4, were isolated through the large-scale sequencing analysis of a human fetal brain cDNA library. The CDK5RAP1_v3 and CDK5RAP1_v4 cDNAs are 1923bp and 1792bp in length, respectively. Sequence analysis revealed that CDK5RAP1_v4 lacked 1 exon, which was present in CDK5RAP1_v3, with the result that these cDNAs encoded different putative proteins. The deduced proteins were 574 amino acids (designated as CDK5RAP1_v3) and 426 amino acids (CDK5RAP1_v4) in length, and shared the 420 N-terminal amino acids. RT-PCR analysis showed that human CDK5RAP1_v3 was widely expressed in human tissues. The expression level of CDK5RAP1_v3 was relatively high in placenta and lung, whereas low levels of expression were detected in heart, brain, liver, skeletal muscle, pancreas, spleen, thymus, small intestine and peripheral blood leukocytes. In contrast, human CDK5RAP1_v4 was mainly expressed in brain, placenta and testis.