Acta chemica Scandinavica (Copenhagen, Denmark : 1989)最新文献_第5页

Sequence-selective interaction between mercury(II) ions and the DNA dodecamer [d(GCCGATATCGGC)]2 studied by 1H NMR spectroscopy. 1H NMR研究了汞(II)离子与DNA十二聚体[d(GCCGATATCGGC)]2的序列选择性相互作用。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-09-01 DOI: 10.3891/acta.chem.scand.50-0775

S Steinkopf, W Nerdal, A Kolstad, E Sletten

{"title":"Sequence-selective interaction between mercury(II) ions and the DNA dodecamer [d(GCCGATATCGGC)]2 studied by 1H NMR spectroscopy.","authors":"S Steinkopf, W Nerdal, A Kolstad, E Sletten","doi":"10.3891/acta.chem.scand.50-0775","DOIUrl":"https://doi.org/10.3891/acta.chem.scand.50-0775","url":null,"abstract":"The palindromic dodecamer [d(GCCGATATCGGC)]2 has been titrated by Hg(ClO4)2 in order to study sequence dependent HgII ion interactions. The titration pattern as monitored by 1D and 2D 1H NMR is consistent with a transition to a new conformer of the dodecamer induced by HgII ions. At intermediate stages of the titration, the proton signals from the new conformer coexist with those of the original one, indicating slow exchange between the two forms on the NMR timescale. The data clearly show that there is no major alteration in the secondary structure, e.g. B-->Z-form or duplex-->hairpin transition. The intra- and inter-residue sequential walk is completed except for a break between T6 and A7. At a concentration level r = [HgII]/[nucleobase] < 0.20 all four central imino signals are present. This definitely excludes thymine N3 as a possible mercuration site. In the imino region of the spectra HgII ions induce a large upfield shift of the thymine imino resonance T8-N3H, while the other thymine resonance T6-N3H is unperturbed. The guanine imino signal G4-N1H shows a large downfield ring current shift caused by major conformational changes in the duplex. The complete titration experiment indicates that mercury, initially, binds selectively to the A5'-T8 base pair. A tentative model is proposed where mercury is cross-linking the two strands via thymine T8-O4 and the deprotonated amino group of the complementary adenine base A5'.","PeriodicalId":76966,"journal":{"name":"Acta chemica Scandinavica (Copenhagen, Denmark : 1989)","volume":"50 9","pages":"775-82"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19785822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Asymmetric organic synthesis with catalytic antibodies. 催化抗体的不对称有机合成。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-08-01 DOI: 10.3891/acta.chem.scand.50-0679

E Keinan, S C Sinha, D Shabat, H Itzhaky, J L Reymond

{"title":"Asymmetric organic synthesis with catalytic antibodies.","authors":"E Keinan, S C Sinha, D Shabat, H Itzhaky, J L Reymond","doi":"10.3891/acta.chem.scand.50-0679","DOIUrl":"https://doi.org/10.3891/acta.chem.scand.50-0679","url":null,"abstract":"The science of catalytic antibodies has undergone a rapid maturation process within its first nine years of existence. From initial 'proof of concept' and demonstration of fundamental, enzyme-like characteristics, antibodies have been shown to catalyze a remarkably broad scope of organic transformations, including difficult and unfavorable chemical reactions. Yet, the ultimate testing ground for new concepts in organic chemistry has always been the synthesis of natural products. Here we focus on several issues related to the applicability of antibody catalysis in organic synthesis. We show that (a) in the hydrophobic environment of the antibody active site, short-lived intermediates can be formed and reacted in a controlled way, thus allowing antibodies to catalyze reactions that are normally incompatible with aqueous media, (b) the intrinsic order of reactivity (chemoselectivity) in a series of structurally related enol ethers and ketals can be inverted from 1:10 in the uncatalyzed hydrolysis reaction to 1000:1 under antibody catalysis, and (c) an efficient total synthesis of alpha-multistriatin, an important, biologically active natural product can be achieved via antibody catalysis.","PeriodicalId":76966,"journal":{"name":"Acta chemica Scandinavica (Copenhagen, Denmark : 1989)","volume":"50 8","pages":"679-87"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19728276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Expression of de novo designed alpha-helical bundles. 从头设计的α -螺旋束的表达。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-08-01 DOI: 10.3891/acta.chem.scand.50-0688

S F Betz, J W Bryson, M C Passador, R J Brown, K T O'Neil, W F DeGrado

引用次数: 5

Catalytic asymmetric aminohydroxylation provides a short taxol side-chain synthesis. 催化不对称氨基羟基化提供了短紫杉醇侧链合成。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-08-01 DOI: 10.3891/acta.chem.scand.50-0649

G Li, K B Sharpless

引用次数: 44

Molecular recognition and assembly. 分子识别和组装。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-08-01 DOI: 10.3891/acta.chem.scand.50-0707

J Rebek

引用次数: 17

Using the process of reactive immunization to induce catalytic antibodies with complex mechanisms: aldolases. 利用反应性免疫过程诱导具有复杂机制的催化抗体:醛缩酶。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-08-01 DOI: 10.3891/acta.chem.scand.50-0672

R A Lerner, C F Barbas

引用次数: 8

Lithofibrin. A new remarkably stable substance found in renal stones. Lithofibrin。一种在肾结石中发现的非常稳定的新物质。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-07-01 DOI: 10.3891/acta.chem.scand.50-0633

S Ohman, L Larsson

{"title":"Lithofibrin. A new remarkably stable substance found in renal stones.","authors":"S Ohman, L Larsson","doi":"10.3891/acta.chem.scand.50-0633","DOIUrl":"https://doi.org/10.3891/acta.chem.scand.50-0633","url":null,"abstract":"Besides inorganic constituents, renal stones contain organic matter known as stone matrix. We have examined such matrix obtained from stones that had been crushed by extracorporeal shock-wave lithotripsy, in order to determine its chemical properties. Morphologically, the matrix was composed of fibers of different colors, most of them exhibiting autofluorescence. Proteins or any other well-known biochemical material were not present. It was remarkably stable against chemical degradation, and could not be dissolved in hot concentrated acids or bases or any common organic solvent. Elementary analysis revealed carbon (60.8%), oxygen (26.9%), nitrogen (7.6%), hydrogen (5.3%) and sulfur (0.77%) to be present. Furthermore, X-ray emission spectroscopy revealed the presence of titanium and chromium. Solid-phase 13C NMR spectroscopy revealed the presence of aromatic and aliphatic carbon as well as carbon bound to O and/or N. The material was paramagnetic. All findings indicated the matrix to be composed of a new class of organic compound, probably a polyaromatic heterocyclic organic material. We welcome suggestions on further methods that can ultimately elucidate the nature of lithofibrins.","PeriodicalId":76966,"journal":{"name":"Acta chemica Scandinavica (Copenhagen, Denmark : 1989)","volume":"50 7","pages":"633-6"},"PeriodicalIF":0.0,"publicationDate":"1996-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19662273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Ether, carbonate and urethane deoxynucleoside derivatives as prodrugs. 作为前药的乙醚、碳酸盐和聚氨酯脱氧核苷衍生物。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-07-01 DOI: 10.3891/acta.chem.scand.50-0609

K Hammer, J Hatlelid, M Grøtli, J Arukwe, J Klaveness, F Rise, K Undheim

引用次数: 9

Synthesis and X-ray structure of 2-(3-methyl-2-butenyl)-3,4,5-trimethoxyphenol: a potent anti-invasive agent against solid tumours. 2-(3-甲基-2-丁烯基)-3,4,5-三甲氧基苯酚的合成和x射线结构:一种有效的实体肿瘤抗侵入剂。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-06-01 DOI: 10.3891/acta.chem.scand.50-0558

V S Parmar, S Gupta, K S Bisht, S Mukherjee, P M Boll, W Errington

引用次数: 8

Synthesis of an AZT-HEPT hybrid and homologous AzddU derivatives. AZT-HEPT杂化物及其同源AzddU衍生物的合成。

Acta chemica Scandinavica (Copenhagen, Denmark : 1989) Pub Date : 1996-05-01 DOI: 10.3891/acta.chem.scand.50-0417

E Larsen, K Danel, G B Vaaben, A A el-Emam, E B Pedersen, C Nielsen

引用次数: 3