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排序方式: 共有642条查询结果,搜索用时 15 毫秒
41.
Shaver YJ Nagpal ML Rudner R Nakamura LK Fox KF Fox A 《Journal of microbiological methods》2002,50(2):215-223
Restriction fragment length polymorphism of rRNA operons (RFLP) and 16S-23S rRNA intergenic region (ISR) sequences of Bacillus subtilis subsp. subtilis, B. subtilis subsp. spizizenii, and B. atrophaeus were compared. ISR sequences of the B. subtilis subspecies were extremely similar (W23 versus 168 rrn H, J, G,W; 96.8%; rrn D, E; 98.4%; rrnB; 97.9%) and, therefore, not useful for their differentiation. However, RFLP of rRNA operons of the B. subtilis subspecies were distinct in terms of numbers and organization within the genome (e.g. the 168 sub-group generally contained 8.3- and 8.0-kb fragments absent in the W23 sub-group). The more distantly related B. atrophaeus was distinct from both B. subtilis subspecies in terms of ISR sequence and rRNA operon number and organization. RFLP of rRNA operons discriminates the two sub-groups of Bacillus subtilis that are indistinguishable by ISR sequence. However, ISR sequence defines the relatedness of B. subtilis to other species (e.g. B. atrophaeus) within the genus Bacillus. 相似文献
42.
Hrishikesh Pandit Sandhya Gopal Archana Sonawani Ajit Kumar Yadav Asif S. Qaseem Himangi Warke Anushree Patil Rahul Gajbhiye Vijay Kulkarni Maha Ahmed Al-Mozaini Susan Idicula-Thomas Uday Kishore Taruna Madan 《PloS one》2014,9(7)
Surfactant Protein SP-D, a member of the collectin family, is a pattern recognition protein, secreted by mucosal epithelial cells and has an important role in innate immunity against various pathogens. In this study, we confirm that native human SP-D and a recombinant fragment of human SP-D (rhSP-D) bind to gp120 of HIV-1 and significantly inhibit viral replication in vitro in a calcium and dose-dependent manner. We show, for the first time, that SP-D and rhSP-D act as potent inhibitors of HIV-1 entry in to target cells and block the interaction between CD4 and gp120 in a dose-dependent manner. The rhSP-D-mediated inhibition of viral replication was examined using three clinical isolates of HIV-1 and three target cells: Jurkat T cells, U937 monocytic cells and PBMCs. HIV-1 induced cytokine storm in the three target cells was significantly suppressed by rhSP-D. Phosphorylation of key kinases p38, Erk1/2 and AKT, which contribute to HIV-1 induced immune activation, was significantly reduced in vitro in the presence of rhSP-D. Notably, anti-HIV-1 activity of rhSP-D was retained in the presence of biological fluids such as cervico-vaginal lavage and seminal plasma. Our study illustrates the multi-faceted role of human SP-D against HIV-1 and potential of rhSP-D for immunotherapy to inhibit viral entry and immune activation in acute HIV infection. 相似文献
43.
Two thioredoxin cDNAs from soybean were isolated by screening an expression library using an anti-(plasma membrane) serum. The nucleotide sequences of the two cDNAs were found to be 89% identical. The polypeptides encoded by the two cDNAs, designated TRX1 and TRX2, contain a disulfide active site, as found in other thioredoxins. TRX1 was expressed as a fusion protein in Escherichia coli and shown to possess thiol-disufide interchange activity. Unlike other eukaryotic thioredoxins, these two soybean thioredoxins contain a putative transmembrane domain in their N-terminal regions. To determine subcellular location, the TRX1 was fused with a reporter epitope at its C-terminus and expressed in transgenic tobacco plants. The fusion protein was co-purified with plasma membrane markers 1,3-glucan synthase and vanadate-sensitive ATPase, indicating the plasma membrane location of TRX1. When the reporter epitope was inserted between the start codon and the transmembrane domain in the N-terminus, the fusion protein was found in the soluble fraction, possibly due to disruption of the transmembrane domain by the highly hydrophilic epitope sequence. Taken together, our results demonstrate that soybean TRX1 is a plasma membrane-bound thioredoxin, which is most likely anchored to the membrane through the N-terminal transmembrane domain. It is known that plant plasma membranes contain various proteins with thiol-disulfide interchange activity. The soybean thioredoxins reported here are the first group of such proteins to be characterized at the molecular level. However, the biological function of the plasma membrane-bound thioredoxin remains to be determined. 相似文献
44.
45.
Non-structural poliovirus 2B protein induces plasma membrane permeabilization and has been recently implicated in triggering apoptosis via the mitochondrial pathway. Here we describe that the pore-forming P3 peptide, based on the 2B amphipathic domain, translocates through the plasma membrane of culture cells and targets mitochondria. Cell permeabilization by P3 versions of different lengths, together with peptide uptake analyses supported an internalization mechanism dependent on P3 capacity to interact physically with lipid bilayers and establish permeating pores therein. Internalized P3 was found associated with mitochondria, but contrary to the parental 2B protein, the short peptide did not affect the morphology or cell distribution of these organelles, nor induced apoptosis. We conclude that P3 constitutes a mitochondriotropic sequence, which is however devoid of 2B pro-apoptotic activity. 相似文献
46.
The crystal structures of alkyl 2-deoxy-α-d-arabino-hexopyranosides, with the alkyl chain lengths from C8 to C18, are established by the single crystal X-ray structural determination. The even-alkyl chain length derivatives crystallized orthorhombic, with space group P212121, whereas the odd-alkyl chain length derivatives crystallized monoclinic, with space group P21. The sugar moieties retained a 4C1 chair conformation and the conformation of the alkyl chains was all-trans. The molecules formed a bilayer structure, in which alkyl chains were interdigitated. The hydrogen bonds, originating from the sugar moieties, were observed in adjacent layers and also within the same layer, resulting in the formation of infinite chains. The alkyl chains arranged parallel to each other and formed planar structures. The thermal properties of the alkyl 2-deoxy glucosides were analyzed further. It was observed that none of the derivatives exhibited mesomorphism. This study establishes that the absence of the hydroxyl group at C-2 of the sugar moiety results in a non-mesogenic nature of the alkyl 2-deoxy-α-d-glycosides, as opposed to the profound mesogenic nature of the normal alkyl glycosides. 相似文献
47.
Structural characterization of AtmS13, a putative sugar aminotransferase involved in indolocarbazole AT2433 aminopentose biosynthesis 下载免费PDF全文
Shanteri Singh Youngchang Kim Fengbin Wang Lance Bigelow Michael Endres Madan K. Kharel Gyorgy Babnigg Craig A. Bingman Andrzej Joachimiak Jon S. Thorson George N. Phillips Jr. 《Proteins》2015,83(8):1547-1554
AT2433 from Actinomadura melliaura is an indolocarbazole antitumor antibiotic structurally distinguished by its unique aminodideoxypentose‐containing disaccharide moiety. The corresponding sugar nucleotide‐based biosynthetic pathway for this unusual sugar derives from comparative genomics where AtmS13 has been suggested as the contributing sugar aminotransferase (SAT). Determination of the AtmS13 X‐ray structure at 1.50‐Å resolution reveals it as a member of the aspartate aminotransferase fold type I (AAT‐I). Structural comparisons of AtmS13 with homologous SATs that act upon similar substrates implicate potential active site residues that contribute to distinctions in sugar C5 (hexose vs. pentose) and/or sugar C2 (deoxy vs. hydroxyl) substrate specificity. Proteins 2015; 83:1547–1554. © 2015 Wiley Periodicals, Inc. 相似文献
48.
Shanteri Singh Karolina Michalska Lance Bigelow Michael Endres Madan K. Kharel Gyorgy Babnigg Ragothaman M. Yennamalli Craig A. Bingman Andrzej Joachimiak Jon S. Thorson George N. Phillips Jr. 《The Journal of biological chemistry》2015,290(43):26249-26258
Classical UDP-glucose 6-dehydrogenases (UGDHs; EC 1.1.1.22) catalyze the conversion of UDP-α-d-glucose (UDP-Glc) to the key metabolic precursor UDP-α-d-glucuronic acid (UDP-GlcA) and display specificity for UDP-Glc. The fundamental biochemical and structural study of the UGDH homolog CalS8 encoded by the calicheamicin biosynthetic gene is reported and represents one of the first studies of a UGDH homolog involved in secondary metabolism. The corresponding biochemical characterization of CalS8 reveals CalS8 as one of the first characterized base-permissive UGDH homologs with a >15-fold preference for TDP-Glc over UDP-Glc. The corresponding structure elucidations of apo-CalS8 and the CalS8·substrate·cofactor ternary complex (at 2.47 and 1.95 Å resolution, respectively) highlight a notably high degree of conservation between CalS8 and classical UGDHs where structural divergence within the intersubunit loop structure likely contributes to the CalS8 base permissivity. As such, this study begins to provide a putative blueprint for base specificity among sugar nucleotide-dependent dehydrogenases and, in conjunction with prior studies on the base specificity of the calicheamicin aminopentosyltransferase CalG4, provides growing support for the calicheamicin aminopentose pathway as a TDP-sugar-dependent process. 相似文献
49.
Reddy BV Rajeswari N Sarangapani M Roopa Reddy G Madan Ch Pranay Kumar K Srinivasa Rao M 《Bioorganic & medicinal chemistry letters》2011,21(21):6510-6514
Indole and its derivatives undergo smooth conjugate addition onto en-1,4-dione derived from isatin and acetophenone, in the presence of a catalytic amount of molecular iodine in acetonitrile under mild conditions to afford a novel class of 3-(1-(1H-indol-3-yl)-2-oxo-2-phenylethyl)indolin-2-one derivatives in good yields with high degree of 1,4-selectivity. Some of these compounds are found to exhibit modest antibacterial and antifungal properties. 相似文献
50.
Huang C Moree WJ Zamani-Kord S Li BF Tucci FC Malany S Wen J Wang H Hoare SR Yang C Madan A Crowe PD Beaton G 《Bioorganic & medicinal chemistry letters》2011,21(3):947-951
Structure-activity relationship studies were conducted to reduce CYP2D6-mediated metabolism in a series of indene H1-antihistamines. Reductions in pKa via incorporation of a β-fluoro substituent or a heteroaryl moiety were shown to reduce contributions to metabolism through this pathway. Several compounds, including 8l, 8o, and 12f were identified with promising primary in vitro profiles and reduced biotransformation via CYP2D6. 相似文献