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991.
Mass spectra of oligonucleotides derived from collision-induced dissociation following electrospray ionization provide an effective means of sequence determination, at the 20-mer level and below. An interactive, stand-alone computer program, Simple Oligonucleotide Sequencer (SOS) has been developed for rapid oligonucleotide sequencing from mass spectra, under user control on a residue by residue basis. Modifications can be defined in any combination for the base, sugar or backbone. Sequence ladders can be independently constructed in both the 5' --> 3' directions and 3' --> 5' directions, and graphically compared for homology and overlap. A particular advantage of this method is the ability to easily erase and rebuild alternate subsequences. The program can be used for ab initio sequencing of modified or unmodified oligonucleotides, for rapid verification of sequence, and in studies of fragmentation processes of model oligonucleotide derivatives. 相似文献
992.
Two rapid screening methods [the TECRA Listeria Visual Immunoassay (LIS-VIS) kit, an AOAC-approved 48 h visual test, which detects Listeria through colorimetry, and BCM Listeria isolation and differentiation plating agar] were used to screen U.S. Food and Drug Administration-regulated commodities for the presence of Listeria spp. Seventy-four different food samples were screened for the presence of Listeria spp. by using both protocols. Test results for the TECRA LIS-VIA showed 66 negative samples and 1 false positive, with 4 confirmed as L. monocytogenes and 3 as L. innocua. With the BCM agar, 67 samples were negative, 4 were confirmed as L. monocytogenes, and 3 were confirmed as L. innocua. Both methods showed similar results and were effective screening tools for Listeria spp. in foods. The BCM agar method proved to be a rapid, sensitive, and excellent tool for early screening and differentiation of Listeria spp. present in foods. 相似文献
993.
A key contact in the active site of an aminoglycoside phosphotransferase enzyme (APH(3')-IIIa) is a pi-pi stacking interaction between Tyr42 and the adenine ring of bound nucleotides. We investigated the prevalence of similar Tyr-adenine contacts and found that many different protein systems employ Tyr residues in the recognition of the adenine ring. The geometry of these stacking interactions suggests that electrostatics play a role in the attraction between these aromatic systems. Kinetic and calorimetric experiments on wild-type and mutant forms of APH(3')-IIIa yielded further experimental evidence of the importance of electrostatics in the adenine binding region and suggested that the stacking interaction contributes approximately 2 kcal/mol of binding energy. This type of information concerning the forces that govern nucleotide binding in APH(3')-IIIa will facilitate inhibitor design strategies that target the nucleotide binding site of APH-type enzymes. 相似文献
994.
Mund G Gabert AJ Batchelor RJ Britten JF Leznoff DB 《Chemical communications (Cambridge, England)》2002,(24):2990-2991
An unusual metal-ligand binding motif is found in dimeric cobalt(II) complexes coordinated by diamidoether ligands that bridge the metals in a 'serpentine' fashion through the ether donors of the ligand backbone rather than the amido groups. 相似文献
995.
The rapid synthesis of 4-aryl-2,2'-bipyridines is described leading to some previously reported compounds in good yields in addition to some new functionalized bipyridines. 相似文献
996.
A vinyl-phenylsilane has been used as a masked vinyl organometallic for a cross coupling reaction with phenyl iodide to provide the cine substitution product in high yield. 相似文献
997.
Topoglidis E Campbell CJ Palomares E Durrant JR 《Chemical communications (Cambridge, England)》2002,(14):1518-1519
Transient optical spectroscopies and photocurrent action spectra are used to demonstrate photoinduced charge separation between zinc-substituted cytochrome c and a nanocrystalline TiO2 electrode. 相似文献
998.
Using split/pool encoded synthesis and a colorimetric catalysis assay, a number of synthetic phosphatase catalysts were developed. 相似文献
999.
Xu X MacLean EJ Teat SJ Nieuwenhuyzen M Chambers M James SL 《Chemical communications (Cambridge, England)》2002,(1):78-79
Addition of anionic benzylsulfate dendrons to dynamic mixtures of Ag+ and triphosphine ligands results in the assembly of loosely-bonded cage-core dendrimers. 相似文献
1000.
Clifford JN Yahioglu G Milgrom LR Durrant JR 《Chemical communications (Cambridge, England)》2002,(12):1260-1261
Modification of the structure of a porphyrin dye shows a significant change in the rate of charge recombination between injected electrons in the TiO2 and the oxidized dye anchored to it following optical excitation, offering an insight into fundamental understanding of processes occurring at the dye/semiconductor interface. 相似文献