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1.
Chiaki Nakano Dr. Tsutomu Hoshino Prof. Dr. 《Chembiochem : a European journal of chemical biology》2009,10(12):2060-2071
The Rv3377c gene from the Mycobacterium tuberculosis H37 genome is specifically limited to those Mycobacterium species that cause tuberculosis. We have demonstrated that the gene product of Rv3377c is a diterpene cyclase that catalyzes the formation of tuberculosinol from geranylgeranyl diphosphate (GGPP). However, the characteristics of this enzyme had not previously been studied in detail with homogeneously purified enzyme. The purified enzyme catalyzed the synthesis of tuberculosinyl diphosphate from GGPP, but it did not bring about the synthesis of tuberculosinol. Optimal conditions for the highest activity were found to be as follows: pH 7.5, 30 °C, MgII (0.1 mM ), and Triton X‐100 (0.1 %). Under these conditions, the kinetic values of KM and kcat were determined to be 11.7±1.9 μM for GGPP and 12.7±0.7 min?1, respectively, whereas the specific activity was 186 nmol min?1 mg?1. The enzyme activity was inhibited at substrate concentrations higher than 50 μM . The catalytic activity was strongly inhibited by 15‐aza‐dihydrogeranylgeraniol and 5‐isopropyl‐N,N,N,2‐tetramethyl‐4‐(piperidine‐1‐carbonyloxy)benzenaminium chloride (Amo‐1618). The DXDTT293–297 motif, corresponding to the DXDDTA motif conserved among terpene cyclases, was mutated in order to investigate its function. The middle D295 was found to be the most crucial entity for the catalysis. D293 and two threonine residues function synergistically to enhance the acidity of D295, possibly through hydrogen‐bonding networks. The Rv3377c enzyme could also react with (14R/S)‐14,15‐oxidoGGPP to generate 3α‐ and 3β‐hydroxytuberculosinyl diphosphate. Conformational analyses were carried out with deuterium‐labeled GGPP and oxidoGGPP. We found that GGPP and (14R)‐oxidoGGPP adopted a chair/chair conformation, but (14S)‐oxidoGGPP adopted a boat/chair conformation. Interestingly, the conformations of oxidoGGPP for the A‐ring formation are the opposite of those of oxidosqualene when it is used as a substrate by squalene cyclases for the biosynthesis of hopene and tetrahymanol. (3R)‐Oxidosqualene is folded in a boat conformation, whereas (3S)‐2,3‐oxidosqualene folds into a chair conformation, for the formation of the A‐rings of the hopene and tetrahymanol skeletons, respectively. 相似文献
2.
Substitution of Two Active‐Site Residues Alters C9‐Hydroxylation in a Class II Diterpene Synthase 下载免费PDF全文
Dr. Sibongile Mafu Emil Fischer Dr. J. Bennett Addison Isabel Riberio Barbosana Dr. Philipp Zerbe 《Chembiochem : a European journal of chemical biology》2016,17(24):2304-2307
Diterpenes form a vast and diverse class of natural products of both ecological and economic importance. Class II diterpene synthase (diTPS) enzymes control the committed biosynthetic reactions underlying diterpene chemical diversity. Homology modelling with site‐directed mutagenesis identified two active‐site residues in the horehound (Marrubium vulgare) class II diTPS peregrinol diphosphate synthase (MvCPS1); residue substitutions abolished the unique MvCPS1‐catalysed water‐capture reaction at C9 and redirected enzyme activity toward formation of an alternative product, halima‐5(10),13‐dienyl diphosphate. These findings contributed new insight into the steric interactions that govern diTPS‐catalysed regiospecific oxygenation reactions and highlight the feasibility of diTPS engineering to provide a broader spectrum of bioactive diterpene natural products. 相似文献
3.
Kyle A. Pelot David M. Hagelthorn Dr. Young J. Hong Dr. Dean J. Tantillo Dr. Philipp Zerbe 《Chembiochem : a European journal of chemical biology》2019,20(1):111-117
The diterpene synthase clerodienyl diphosphate synthase 1 (PvCPS1) from the crop plant switchgrass (Panicum virgatum) stereoselectively converts (E,E,E)-geranylgeranyl diphosphate (GGPP) into the clerodane natural product, cis-trans-clerodienyl diphosphate (CLPP, 1 ). Structure-guided point mutations of PvCPS1 redirected product stereoselectivity toward the formation of a rare cis-clerodane diastereomer, cis-cis-CLPP ( 2 ). Additionally, an alternative cis-clerodane diastereomer, (5S,8S,9R,10R)-13Z-CLPP ( 3 ), was produced when treating PvCPS1 and select variants thereof with the cis-prenyl substrate (Z,Z,Z)-nerylneryl diphosphate (NNPP). These results support the hypothesis that substrate configuration and minor active-site alterations impact precatalysis substrate folding in the stereoselective biosynthesis of clerodane diterpenoid scaffolds, and can be employed to provide enzymatic access to a broader range of bioactive clerodane natural products. 相似文献
4.
Noike M Liu C Ono Y Hamano Y Toyomasu T Sassa T Kato N Dairi T 《Chembiochem : a European journal of chemical biology》2012,13(4):566-573
Isoprenoids form the largest family of compounds found in nature. Isoprenoids are often attached to other moieties such as aromatic compounds, indoles/tryptophan, and flavonoids. These reactions are catalyzed by three phylogenetically distinct prenyltransferases: soluble aromatic prenyltransferases identified mainly in actinobacteria, soluble indole prenyltransferases mostly in fungi, and membrane‐bound prenyltransferases in various organisms. Fusicoccin A (FC A) is a diterpene glycoside produced by the plant‐pathogenic fungus Phomopsis amygdali and has a unique O‐prenylated glucose moiety. In this study, we identified for the first time, from a genome database of P. amygdali, a gene (papt) encoding a prenyltransferase that reversibly transfers dimethylallyl diphosphate (DMAPP) to the 6′‐hydroxy group of the glucose moiety of FC A to yield an O‐prenylated sugar. An in vitro assay with a recombinant enzyme was also developed. Detailed analyses with recombinant PAPT showed that the enzyme is likely to be a monomer and requires no divalent cations. The optimum pH and temperature were 8.0 and 50 °C, respectively. Km values were calculated as 0.49±0.037 μM for FC P (a plausible intermediate of FC A biosynthesis) and 8.3±0.63 μM for DMAPP, with a kcat of 55.3±3.3×10?3 s. The enzyme did not act on representative substrates of the above‐mentioned three types of prenyltransferase, but showed a weak transfer activity of geranyl diphosphate to FC P. 相似文献
5.
Tohru Abe Sadamu Ozaki Assist. Prof. Daijiro Ueda Prof. Tsutomu Sato 《Chembiochem : a European journal of chemical biology》2020,21(20):2931-2938
Comprehensive functional analyses of E-isoprenyl diphosphate synthases (E-IDSs) from nonpathogenic Mycobacterium vanbaalenii have been performed. Mv0992 and Mv1577 represent a nonaprenyl diphosphate (E-C45) synthase and a geranylgeranyl diphosphate (E-C20) synthase, respectively. Although Mv3536 was identified as an E-C20 synthase using a single enzyme, co-incubation of Mv3536 and Z-IDSs (Mv4662 and Mv3822) strongly suggested it releases an intermediate geranyl diphosphate (E-C10) during a continuous condensation reaction. Mv0992 and Mv3536 functions differed from those of the previously reported pathogenic Mycobacterium tuberculosis homologues Rv0562 and Rv2173, respectively. Re-analysis of Rv0562 and Rv2173 demonstrated that their functions were similar to those of Mv0992 and Mv3536 (Rv0562: E-C45 synthase; Rv2173: E-C10–15 synthase). The newly proposed functions of Rv0562 and Rv2173 would be in the biosynthesis of menaquinone and glycosyl carrier lipids essential for growth. Furthermore, a reduced allylic diphosphate could be used as the Z-IDS of the Mv3822 substrate, thereby introducing a potentially novel pathway of cyclic sesquarterpene biosynthesis. 相似文献
6.
Identification of the Target Protein of Agelasine D,a Marine Sponge Diterpene Alkaloid,as an Anti‐dormant Mycobacterial Substance 下载免费PDF全文
Dr. Masayoshi Arai Yoshi Yamano Dr. Andi Setiawan Prof. Dr. Motomasa Kobayashi 《Chembiochem : a European journal of chemical biology》2014,15(1):117-123
One of the major reasons for the wide epidemicity of tuberculosis and for the necessity for extensive chemotherapeutic regimens is that the causative agent, Mycobacterium tuberculosis, has an ability to become dormant. Therefore, new lead compounds that are anti‐bacterial against M. tuberculosis in both active and dormant states are urgently needed. Marine sponge diterpene alkaloids, agelasines B, C, and D, from an Indonesian marine sponge of the genus Agelas were rediscovered as anti‐dormant‐mycobacterial substances. Based on the concept that the transformants over‐expressing targets of antimicrobial substances confer drug resistance, strains resistant to agelasine D were screened from Mycobacterium smegmatis transformed with a genomic DNA library of Mycobacterium bovis BCG. Sequence analysis of the cosmids isolated from resistant transformants revealed that the responsible gene was located in the genome region between 3475.051 and 3502.901 kb. Further analysis of the transformants over‐expressing the individual gene contained in this region indicated that BCG3185c (possibly a dioxygenase) might be a target of the molecule. Moreover, agelasine D was found to bind directly to recombinant BCG3185c protein (KD 2.42 μm), based on surface plasmon resonance (SPR). This evidence strongly suggests that the BCG3185c protein is the major target of agelasine D, and that the latter is the anti‐mycobacterial substance against dormant bacilli. 相似文献
7.
Momoka Yamane Dr. Atsushi Minami Dr. Chengwei Liu Dr. Taro Ozaki Ichiro Takeuchi Tae Tsukagoshi Dr. Tetsuo Tokiwano Prof. Dr. Katsuya Gomi Prof. Dr. Hideaki Oikawa 《Chembiochem : a European journal of chemical biology》2017,18(23):2317-2322
The diterpene pleuromutilin is a ribosome‐targeting antibiotic isolated from basidiomycete fungi, such as Clitopilus pseudo‐pinsitus. The functional characterization of all biosynthetic enzymes involved in pleuromutilin biosynthesis is reported and a biosynthetic pathway proposed. In vitro enzymatic reactions and mutational analysis revealed that a labdane‐related diterpene synthase, Ple3, catalyzed two rounds of cyclization from geranylgeranyl diphosphate to premutilin possessing a characteristic 5–6–8‐tricyclic carbon skeleton. Biotransformation experiments utilizing Aspergillus oryzae transformants possessing modification enzyme genes allowed the biosynthetic pathway from premutilin to pleuromutilin to be proposed. The present study sets the stage for the enzymatic synthesis of natural products isolated from basidiomycete fungi, which are a prolific source of structurally diverse and biologically active terpenoids. 相似文献
8.
Development of Potent Inhibitors of the Mycobacterium tuberculosis Virulence Factor Zmp1 and Evaluation of Their Effect on Mycobacterial Survival inside Macrophages 下载免费PDF全文
Dr. Marco Paolino Dr. Margherita Brindisi Dr. Alessandra Vallone Prof. Stefania Butini Prof. Giuseppe Campiani Dr. Chiara Nannicini Germano Giuliani Prof. Maurizio Anzini Dr. Stefania Lamponi Prof. Gianluca Giorgi Prof. Diego Sbardella Dr. Davide M. Ferraris Prof. Stefano Marini Prof. Massimo Coletta Dr. Ivana Palucci Dr. Mariachiara Minerva Prof. Giovanni Delogu Dr. Ilaria Pepponi Dr. Delia Goletti Prof. Andrea Cappelli Sandra Gemma Dr. Simone Brogi 《ChemMedChem》2018,13(5):422-430
The enzyme Zmp1 is a zinc‐containing peptidase that plays a critical role in the pathogenicity of Mycobacterium tuberculosis. Herein we describe the identification of a small set of Zmp1 inhibitors based on a novel 8‐hydroxyquinoline‐2‐hydroxamate scaffold. Among the synthesized compounds, N‐(benzyloxy)‐8‐hydroxyquinoline‐2‐carboxamide ( 1 c ) was found to be the most potent Zmp1 inhibitor known to date, and its binding mode was analyzed both by kinetics studies and molecular modeling, identifying critical interactions of 1 c with the zinc ion and residues in the active site. The effect of 1 c on intracellular Mycobacterium survival was assayed in J774 murine macrophages infected with M. tuberculosis H37Rv or M. bovis BCG and human monocyte‐derived macrophages infected with M. tuberculosis H37Rv. Cytotoxicity and genotoxicity were also assessed. Overall, inhibitor 1 c displays interesting in vitro antitubercular properties worthy of further investigation. 相似文献
9.
Julia Winkelblech Mike Liebhold Jakub Gunera Xiulan Xie Peter Kolb Shu‐Ming Li 《Advanced Synthesis \u0026amp; Catalysis》2015,357(5):975-986
The behavior of four dimethylallyltryptophan synthases (DMATSs) (5‐DMATS and 5‐DMATSSc as tryptophan C5‐prenyltransferases, and 6‐DMATSSa and 6‐DMATSSv as C6‐prenyltransferases) and one L ‐tyrosine prenyltransferase with a tryptophan C7‐prenyltransferase activity was investigated in the presence of two unnatural alkyl donors (methylallyl and 2‐pentenyl diphosphate) and one benzyl donor (benzyl diphosphate). Detailed biochemical investigations revealed the acceptance of these dimethylallyl diphosphate (DMAPP) analogues by all tested enzymes with different relative activities. Enzyme products with the allyl or benzyl moiety attached to different positions were identified in the reaction mixtures, whereby C‐6 alkylated or benzylated L ‐tryptophan was found as one of the main products. This observation demonstrates a preference of the five prenyltransferases toward C‐6 of the indole ring in the presence of unnatural DMAPP derivatives. Molecular dynamics simulation experiments with a homologous model of 5‐DMATS explained well its reactions with methylallyl and 2‐pentenyl diphosphate. Furthermore this study expands significantly the potential usage of tryptophan prenylating enzymes as biocatalysts for Friedel–Crafts alkylation.
10.
Christopher J. Schwalen Dr. Xinxin Feng Dr. Weidong Liu Bing O‐Dowd Dr. Tzu‐Ping Ko Christopher J. Shin Prof. Dr. Rey‐Ting Guo Prof. Dr. Douglas A. Mitchell Prof. Dr. Dr. Eric Oldfield 《Chembiochem : a European journal of chemical biology》2017,18(11):985-991
Many organisms contain head‐to‐head isoprenoid synthases; we investigated three such types of enzymes from the pathogens Neisseria meningitidis, Neisseria gonorrhoeae, and Enterococcus hirae. The E. hirae enzyme was found to produce dehydrosqualene, and we solved an inhibitor‐bound structure that revealed a fold similar to that of CrtM from Staphylococcus aureus. In contrast, the homologous proteins from Neisseria spp. carried out only the first half of the reaction, yielding presqualene diphosphate (PSPP). Based on product analyses, bioinformatics, and mutagenesis, we concluded that the Neisseria proteins were HpnDs (PSPP synthases). The differences in chemical reactivity to CrtM were due, at least in part, to the presence of a PSPP‐stabilizing arginine in the HpnDs, decreasing the rate of dehydrosqualene biosynthesis. These results show that not only S. aureus but also other bacterial pathogens contain head‐to‐head prenyl synthases, although their biological functions remain to be elucidated. 相似文献
11.
Janish Desai Dr. Yang Wang Dr. Ke Wang Dr. Satish R. Malwal Prof. Eric Oldfield 《ChemMedChem》2016,11(19):2205-2215
We synthesized potential inhibitors of farnesyl diphosphate synthase (FPPS), undecaprenyl diphosphate synthase (UPPS), or undecaprenyl diphosphate phosphatase (UPPP), and tested them in bacterial cell growth and enzyme inhibition assays. The most active compounds were found to be bisphosphonates with electron‐withdrawing aryl‐alkyl side chains which inhibited the growth of Gram‐negative bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) at ~1–4 μg mL?1 levels. They were found to be potent inhibitors of FPPS; cell growth was partially “rescued” by the addition of farnesol or overexpression of FPPS, and there was synergistic activity with known isoprenoid biosynthesis pathway inhibitors. Lipophilic hydroxyalkyl phosphonic acids inhibited UPPS and UPPP at micromolar levels; they were active (~2–6 μg mL?1) against Gram‐positive but not Gram‐negative organisms, and again exhibited synergistic activity with cell wall biosynthesis inhibitors, but only indifferent effects with other inhibitors. The results are of interest because they describe novel inhibitors of FPPS, UPPS, and UPPP with cell growth inhibitory activities as low as ~1–2 μg mL?1. 相似文献
12.
Spectroscopic and Computational Investigations of Ligand Binding to IspH: Discovery of Non‐diphosphate Inhibitors 下载免费PDF全文
Bing O'Dowd Sarah Williams Dr. Hongxin Wang Joo Hwan No Guodong Rao Weixue Wang Prof. Dr. J. Andrew McCammon Prof. Dr. Stephen P. Cramer Prof. Dr. Eric Oldfield 《Chembiochem : a European journal of chemical biology》2017,18(10):914-920
Isoprenoid biosynthesis is an important area for anti‐infective drug development. One isoprenoid target is (E)‐1‐hydroxy‐2‐methyl‐but‐2‐enyl 4‐diphosphate (HMBPP) reductase (IspH), which forms isopentenyl diphosphate and dimethylallyl diphosphate from HMBPP in a 2H+/2e? reduction. IspH contains a 4 Fe?4 S cluster, and in this work, we first investigated how small molecules bound to the cluster by using HYSCORE and NRVS spectroscopies. The results of these, as well as other structural and spectroscopic investigations, led to the conclusion that, in most cases, ligands bound to IspH 4 Fe?4 S clusters by η1 coordination, forming tetrahedral geometries at the unique fourth Fe, ligand side chains preventing further ligand (e.g., H2O, O2) binding. Based on these ideas, we used in silico methods to find drug‐like inhibitors that might occupy the HMBPP substrate binding pocket and bind to Fe, leading to the discovery of a barbituric acid analogue with a Ki value of ≈500 nm against Pseudomonas aeruginosa IspH. 相似文献
13.
Evelyn Yu-Wen Huang Dr. Brooke X. C. Kwai Dr. Ram Prasad Bhusal Dr. Ghader Bashiri Dr. Ivanhoe K. H. Leung 《Chembiochem : a European journal of chemical biology》2023,24(14):e202300162
Isocitrate lyase (ICL) isoform 2 is an essential enzyme for some clinical Mycobacterium tuberculosis (Mtb) strains during infection. In the laboratory Mtb strain H37Rv, the icl2 gene encodes two distinct gene products – Rv1915 and Rv1916 – due to a frameshift mutation. This study aims to characterise these two gene products to understand their structure and function. While we were unable to produce Rv1915 recombinantly, soluble Rv1916 was obtained with sufficient yield for characterisation. Kinetic studies using UV-visible spectrophotometry and 1H-NMR spectroscopy showed that recombinant Rv1916 does not possess isocitrate lyase activity, while waterLOGSY binding experiments demonstrated that it could bind acetyl-CoA. Finally, X-ray crystallography revealed structural similarities between Rv1916 and the C-terminal domain of ICL2. Considering the probable differences between full-length ICL2 and the gene products Rv1915 and Rv1916, care must be taken when using Mtb H37Rv as a model organism to study central carbon metabolism. 相似文献
14.
Tsutomu Sato Dr. Kazuo Takizawa Yuriko Orito Hanayo Kudo Tsutomu Hoshino Prof. Dr. 《Chembiochem : a European journal of chemical biology》2010,11(13):1874-1881
Nonpathogenic Mycobacterium species produce rare cyclic C35 terpenes that are biosynthesized by cyclization of Z‐type C35 polyprenyl diphosphate. To provide deeper insight into the biosynthesis of C35 terpenes, we carried out functional analyses of three Z‐prenyltransferase homologues in M. vanbaalenii identified by genomic analysis. Mvan_3822, a novel bifunctional Z‐prenyltransferase, biosynthesizes C35‐heptaprenyl diphosphate as a main product from (E,E)‐farnesyl diphosphate (E,E‐FPP) and (E,E,E)‐geranylgeranyl diphosphate (E,E,E‐GGPP), but produces a C50‐decaprenyl diphosphate from geranyl diphosphate. Mvan_1705 is a novel Z,E,E‐GGPP synthase. In addition, novel cyclic C35 terpenes, (14E)‐ and (14Z)‐dehydroheptaprenylcycline, were identified as minor metabolites in nonpathogenic Mycobacterium cells. C35 terpenes could be biosynthesized by two routes, in which E and Z geometric isomers of heptaprenyl diphosphate are produced from E,E‐FPP and E,E,E‐GGPP, and the prenylreductase responsible for the biosynthesis of C35 terpenes could reduce both E and Z prenyl residues. 相似文献
15.
An Improved Technique for the Rapid Chemical Characterisation of Bacterial Terpene Cyclases 下载免费PDF全文
Dr. Jeroen S. Dickschat Dr. Khomaizon A. K. Pahirulzaman Patrick Rabe Tim A. Klapschinski 《Chembiochem : a European journal of chemical biology》2014,15(6):810-814
A derivative of the pET28c(+) expression vector was constructed. It contains a yeast replication system (2μ origin of replication) and a yeast selectable marker (URA3), and can be used for gene cloning in yeast by efficient homologous recombination, and for heterologous expression in E. coli. The vector was used for the expression and chemical characterisation of three bacterial terpene cyclases. 相似文献
16.
Hang Jiang Takaya Sugiyama Akinari Hamajima Yasumasa Hamada 《Advanced Synthesis \u0026amp; Catalysis》2011,353(1):155-162
The Shi‐type epoxidation of O‐tert‐butyldiphenylsilyl (TBDPS) protected o‐allylphenols serves as an efficient strategy to construct the dihydrobenzofurans and dihydrobenzopyrans in up to 97% ee. This methodology led to the enantioselective synthesis of (+)‐marmesin, (−)‐(3′R)‐decursinol, and (+)‐lomatin. 相似文献
17.
Dr. Lluís Ballell Dr. Robert H. Bates Dr. Rob J. Young Daniel Alvarez‐Gomez Dr. Emilio Alvarez‐Ruiz Vanessa Barroso Delia Blanco Benigno Crespo Dr. Jaime Escribano Rubén González Sonia Lozano Dr. Sophie Huss Angel Santos‐Villarejo Dr. José Julio Martín‐Plaza Dr. Alfonso Mendoza Dr. María José Rebollo‐Lopez Dr. Modesto Remuiñan‐Blanco Dr. José Luis Lavandera Dr. Esther Pérez‐Herran Dr. Francisco Javier Gamo‐Benito Dr. José Francisco García‐Bustos Dr. David Barros Dr. Julia P. Castro Dr. Nicholas Cammack 《ChemMedChem》2013,8(2):313-321
With the aim of fuelling open‐source, translational, early‐stage drug discovery activities, the results of the recently completed antimycobacterial phenotypic screening campaign against Mycobacterium bovis BCG with hit confirmation in M. tuberculosis H37Rv were made publicly accessible. A set of 177 potent non‐cytotoxic H37Rv hits was identified and will be made available to maximize the potential impact of the compounds toward a chemical genetics/proteomics exercise, while at the same time providing a plethora of potential starting points for new synthetic lead‐generation activities. Two additional drug‐discovery‐relevant datasets are included: a) a drug‐like property analysis reflecting the latest lead‐like guidelines and b) an early lead‐generation package of the most promising hits within the clusters identified. 相似文献
18.
Characterization of the Gene Cluster CYP264B1‐geoA from Sorangium cellulosum So ce56: Biosynthesis of (+)‐Eremophilene and Its Hydroxylation 下载免费PDF全文
Alexander Schifrin Dr. Thuy T. B. Ly Dr. Nils Günnewich Dr. Josef Zapp Dr. Verena Thiel Prof. Dr. Stefan Schulz Dr. Frank Hannemann Dr. Yogan Khatri Prof. Dr. Rita Bernhardt 《Chembiochem : a European journal of chemical biology》2015,16(2):337-344
Terpenoids can be found in almost all forms of life; however, the biosynthesis of bacterial terpenoids has not been intensively studied. This study reports the identification and functional characterization of the gene cluster CYP264B1–geoA from Sorangium cellulosum So ce56. Expression of the enzymes and synthesis of their products for NMR analysis and X‐ray diffraction were carried out by employing an Escherichia coli whole‐cell conversion system that provides the geoA substrate farnesyl pyrophosphate through simultaneous overexpression of the mevalonate pathway genes. The geoA product was identified as a novel sesquiterpene, and assigned NMR signals unambiguously proved that geoA is an (+)‐eremophilene synthase. The very tight binding of (+)‐eremophilene (~0.40 μM ), which is also available in S. cellulosum So ce56, and its oxidation by CYP264B1 suggest that the CYP264B1–geoA gene cluster is required for the biosynthesis of (+)‐eremophilene derivatives. 相似文献
19.
To prepare silica beads covered with a lysozyme‐imprinted polymer layer, we polymerized acrylamide and acrylic acid or acrylamide and N,N‐dimethylaminopropylacrylamide with (NH4)2S2O8 in a phosphate buffer containing the lysozyme, surface‐modified silica beads, and crosslinkers; the result was the formation of a polymer layer with a lysozyme recognition site on the silica‐bead surface. By quantitative analysis of the supernatant of the solution containing the silica beads, we confirmed that modified silica beads, in contrast to unmodified silica beads, can selectively adsorb lysozymes. The process of binding and releasing the lysozyme to and from the modified silica beads can be repeated several times without degradation of the rebinding ability. A quartz‐crystal microbalance sensor fabricated with a molecularly imprinted polymer layer with a lysozyme recognition site was prepared. When a lysozyme aqueous solution was added to the solution in which the sensor was immersed, a high level of sensitivity and response was observed. High selectivity was also demonstrated by tests with other protein solutions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3378–3387, 2001 相似文献
20.
Bacterial Cell Growth Inhibitors Targeting Undecaprenyl Diphosphate Synthase and Undecaprenyl Diphosphate Phosphatase 下载免费PDF全文
Dr. Yang Wang Janish Desai Yonghui Zhang Dr. Satish R. Malwal Christopher J. Shin Dr. Xinxin Feng Hong Sun Guizhi Liu Prof. Rey‐Ting Guo Prof. Eric Oldfield 《ChemMedChem》2016,11(20):2311-2319
We synthesized a series of benzoic acids and phenylphosphonic acids and investigated their effects on the growth of Staphylococcus aureus and Bacillus subtilis. One of the most active compounds, 5‐fluoro‐2‐(3‐(octyloxy)benzamido)benzoic acid ( 7 , ED50~0.15 μg mL?1) acted synergistically with seven antibiotics known to target bacterial cell‐wall biosynthesis (a fractional inhibitory concentration index (FICI) of ~0.35, on average) but had indifferent effects in combinations with six non‐cell‐wall biosynthesis inhibitors (average FICI~1.45). The most active compounds were found to inhibit two enzymes involved in isoprenoid/bacterial cell‐wall biosynthesis: undecaprenyl diphosphate synthase (UPPS) and undecaprenyl diphosphate phosphatase (UPPP), but not farnesyl diphosphate synthase, and there were good correlations between bacterial cell growth inhibition, UPPS inhibition, and UPPP inhibition. 相似文献