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排序方式: 共有887条查询结果,搜索用时 35 毫秒
811.
Jiang J Lin P Hoang M Chang L Tan C Feighner S Palyha OC Hreniuk DL Pan J Sailer AW Morin NR MacNeil DJ Howard AD Van der Ploeg LH Goulet MT DeVita RJ 《Bioorganic & medicinal chemistry letters》2006,16(20):5275-5279
Structure-activity relationships of a 4-aminoquinoline MCH1R antagonist lead series were explored by synthesis of analogs with modifications at the 2-, 4-, and 6-positions of the original HTS hit. Improvements to the original screening lead included lipophilic groups at the 2-position and biphenyl, cyclohexyl phenyl, and hydrocinnamyl carboxamides at the 6-position. Modifications of the 4-amino group were not well tolerated. 相似文献
812.
Two plasmid-based expression vectors have been constructed where one allows intracellular production of recombinant proteins while the second directs the proteins into the culture medium. Both vectors use the strong promoter preceding the groESL operon (codes for the essential heat shock proteins GroES and GroEL) of Bacillus subtilis fused to the lac operator allowing their induction by addition of ITPG. While the background level of expression of these expression cassettes is very low in the absence of the inducer, an induction factor of about 1300 was measured. When the genes htpG and pbpE (coding for a heat shock protein and a penicillin-binding protein, respectively) were fused to the groE promoter, the amount of recombinant protein produced after addition of IPTG represented 10 and 13%, respectively, of the total cellular protein. To obtain secretion of recombinant proteins, the coding region for the signal peptide of the amyQ gene encoding an alpha-amylase from Bacillus amyloliquefasciens was fused to the groE promoter. High-level secretion of amyQ alpha-amylase and cellulase A and B of Clostridium thermocellum was demonstrated. 相似文献
813.
P. Thanigaimalai Tuan Anh Le Hoang Ki-Cheul Lee Seong-Cheol Bang Vinay K. Sharma Cheong-Yong Yun Eunmiri Roh Bang-Yeon Hwang Youngsoo Kim Sang-Hun Jung 《Bioorganic & medicinal chemistry letters》2010,20(9):2991-2993
In order to define the structural requirements of phenylthiourea (PTU), a series of thiourea and thiosemicarbazone analogs were prepared and evaluated as inhibitors of melanogenesis in melanoma B16 cells. The most potent analog was 2-(4-tert-butylbenzylidene)hydrazinecarbothioamide (1u) with an IC50 value of 2.7 μM in inhibition of melanogenesis. The structure for potent inhibitory activity of these derivatives are required with the direct connection of π-planar structure to thiourea without steric hinderance in PTU derivatives and the hydrophobic substituent at para position in case of semicarbazones. 相似文献
814.
815.
Scott K. Thompson David G. Washburn James S. Frazee Kevin P. Madauss Tram H. Hoang Leahann Lapinski Eugene T. Grygielko Lindsay E. Glace Walter Trizna Shawn P. Williams Chaya Duraiswami Jeffrey D. Bray Nicholas J. Laping 《Bioorganic & medicinal chemistry letters》2009,19(16):4777-4780
Using the X-ray crystal structure of an amide-based progesterone receptor (PR) partial agonist bound to the PR ligand binding domain, a novel PR partial agonist class containing a pyrrolidine ring was designed. Members of this class of N-alkylpyrrolidines demonstrate potent and highly selective partial agonism of the progesterone receptor, and one of these analogs was shown to be efficacious upon oral dosing in the OVX rat model of estrogen opposition. 相似文献
816.
David G. Washburn Tram H. Hoang Nino Campobasso Angela Smallwood Derek J. Parks Christine L. Webb Kelly A. Frank Melanie Nord Chaya Duraiswami Christopher Evans Michael Jaye Scott K. Thompson 《Bioorganic & medicinal chemistry letters》2009,19(4):1097-1100
A novel series of 1H-indol-1-yl tertiary amine LXR agonists has been designed. Compounds from this series were potent agonists with good rat pharmacokinetic parameters. In addition, the crystal structure of an LXR agonist bound to LXRα will be disclosed. 相似文献
817.
Preference for NH4+ or NO3− nutrition by the perennial legume Sesbania sesban (L.) Merr. was assessed by supplying plants with NH4+ and NO3− alone or mixed at equal concentrations (0.5 mM) in hydroponic culture. In addition, growth responses of S. sesban to NH4+ and NO3− nutrition and the effects on root nodulation and nutrient and mineral composition of the plant tissues were evaluated in a hydroponic setup at a range of external concentration of NH4+ and NO3− (0, 0.1, 0.2, 0.5, 2 and 5 mM). Seedlings of S. sesban grew equally well when supplied with either NH4+ or NO3− alone or mixed and had high relative growth rates (RGRs) ranging between 0.19 and 0.21 d−1. When larger plants of S. sesban were supplied with NH4+ or NO3− alone, the RGRs and shoot elongation rates were not affected by the external concentration of inorganic N. At external N concentrations up to 0.5 mM nodulation occurred and contributed to the N nutrition through fixation of gaseous N2 from the atmosphere. For both NH4+ and NO3−-fed plants the N concentration in the plant tissues, particularly water-extractable NO3−, increased at high supply concentrations, and concentrations of mineral cations generally decreased. It is concluded that S. sesban can grow without an external inorganic N supply by fixing atmospheric N2 gas via root nodules. Also, S. sesban grows well on both NH4+ and NO3− as the external N source and the plant can tolerate relatively high concentrations of NH4+. This wide ecological amplitude concerning N nutrition makes S. sesban very useful as a N2-fixing fallow crop in N deficient areas and also a candidate species for use in constructed wetland systems for the treatment of NH4+ rich waters. 相似文献
818.
Characterization of a Pseudomonas aeruginosa Fatty Acid Biosynthetic Gene Cluster: Purification of Acyl Carrier Protein (ACP) and Malonyl-Coenzyme A:ACP Transacylase (FabD) 下载免费PDF全文
Alecksandr J. Kutchma Tung T. Hoang Herbert P. Schweizer 《Journal of bacteriology》1999,181(17):5498-5504
A DNA fragment containing the Pseudomonas aeruginosa fabD (encoding malonyl-coenzyme A [CoA]:acyl carrier protein [ACP] transacylase), fabG (encoding beta-ketoacyl-ACP reductase), acpP (encoding ACP), and fabF (encoding beta-ketoacyl-ACP synthase II) genes was cloned and sequenced. This fab gene cluster is delimited by the plsX (encoding a poorly understood enzyme of phospholipid metabolism) and pabC (encoding 4-amino-4-deoxychorismate lyase) genes; the fabF and pabC genes seem to be translationally coupled. The fabH gene (encoding beta-ketoacyl-ACP synthase III), which in most gram-negative bacteria is located between plsX and fabD, is absent from this gene cluster. A chromosomal temperature-sensitive fabD mutant was obtained by site-directed mutagenesis that resulted in a W258Q change. A chromosomal fabF insertion mutant was generated, and the resulting mutant strain contained substantially reduced levels of cis-vaccenic acid. Multiple attempts aimed at disruption of the chromosomal fabG gene were unsuccessful. We purified FabD as a hexahistidine fusion protein (H6-FabD) and ACP in its native form via an ACP-intein-chitin binding domain fusion protein, using a novel expression and purification scheme that should be applicable to ACP from other bacteria. Matrix-assisted laser desorption-ionization spectroscopy, native polyacrylamide electrophoresis, and amino-terminal sequencing revealed that (i) most of the purified ACP was properly modified with its 4'-phosphopantetheine functional group, (ii) it was not acylated, and (iii) the amino-terminal methionine was removed. In an in vitro system, purified ACP functioned as acyl acceptor and H(6)-FabD exhibited malonyl-CoA:ACP transacylase activity. 相似文献
819.
820.