Basic life sciences最新文献_第4页

Chemical constituents of mainly active component fractionated from the aqueous tea non-dialysates, an antitumor promoter. 化学成分主要是从茶叶中分离出的活性成分，具有抗肿瘤促进剂作用。

Basic life sciences Pub Date : 1999-01-01 DOI: 10.1007/978-1-4615-4139-4_35

Y Nakamura, M Matsuda, T Honma, I Tomita, N Shibata, T Warashina, T Noro, Y Hara

引用次数: 5

Understanding water: molecular dynamics simulations of myoglobin. 理解水:肌红蛋白的分子动力学模拟。

Basic life sciences Pub Date : 1996-01-01

W Gu, A E Garcia, B P Schoenborn

引用次数: 0

High-level expression and deuteration of sperm whale myoglobin. A study of its solvent structure by X-ray and neutron diffraction methods. 抹香鲸肌红蛋白的高水平表达和氘化。用x射线和中子衍射法研究其溶剂结构。

Basic life sciences Pub Date : 1996-01-01

F Shu, V Ramakrishnan, B P Schoenborn

{"title":"High-level expression and deuteration of sperm whale myoglobin. A study of its solvent structure by X-ray and neutron diffraction methods.","authors":"F Shu, V Ramakrishnan, B P Schoenborn","doi":"","DOIUrl":"","url":null,"abstract":"Neutron diffraction has become one of the best ways to study light atoms, such as hydrogens. Hydrogen however has a negative coherent scattering factor, and a large incoherent scattering factor, while deuterium has virtually no incoherent scattering, but a large positive coherent scattering factor. Beside causing high background due to its incoherent scattering, the negative coherent scattering of hydrogen tends to cancel out the positive contribution from other atoms in a neutron density map. Therefore a fully deuterated sample will yield better diffraction data with stronger density in the hydrogen position. On this basis, a sperm whale myoglobin gene modified to include part of the A c11 protein gene has been cloned into the T7 expression system. Milligram amounts of fully deuterated holo-myoglobin have been obtained and used for crystallization. The synthetic sperm whale myoglobin crystallized in P2(1) space group isomorphous with the native protein crystal. A complete X-ray diffraction dataset at 1.5A has been collected. This X-ray dataset, and a neutron data set collected previously on a protonated carbon-monoxymyoglobin crystal have been used for solvent structure studies. Both X-ray and neutron data have shown that there are ordered hydration layers around the protein surface. Solvent shell analysis on the neutron data further has shown that the first hydration layer behaves differently around polar and apolar regions of the protein surface. Finally, the structure of per-deuterated myoglobin has been refined using all reflections to a R factor of 17%.","PeriodicalId":8697,"journal":{"name":"Basic life sciences","volume":"64 ","pages":"309-23"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19988972","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: 0

Theoretical description of biomolecular hydration. Application to A-DNA. 生物分子水合作用的理论描述。A-DNA的应用。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_26

A E Garcia, G Hummer, D M Soumpasis

引用次数: 5

Neutrons in biology. A perspective. 生物学中的中子。一个透视图。

Basic life sciences Pub Date : 1996-01-01

R B Knott, B P Schoenborn

引用次数: 0

Neutron diffraction studies of amphipathic helices in phospholipid bilayers. 磷脂双层中两性螺旋的中子衍射研究。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_17

J P Bradshaw, K C Duff, P J Gilchrist, A M Saxena

引用次数: 7

Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol. 小疏水分子在含胆固醇的脂质双层中的嵌入。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_20

D L Worcester, K Hamacher, H Kaiser, R Kulasekere, J Torbet

引用次数: 1

Neutron anatomy. 中子解剖学。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_2

G E Bacon

{"title":"Neutron anatomy.","authors":"G E Bacon","doi":"10.1007/978-1-4615-5847-7_2","DOIUrl":"https://doi.org/10.1007/978-1-4615-5847-7_2","url":null,"abstract":"The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content-the crystals of the hexagonal hydroxyapatite- and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilising distances ranging from 1 mm to 10 mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals-including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighbouring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction, for a sample of bone.","PeriodicalId":8697,"journal":{"name":"Basic life sciences","volume":"64 ","pages":"17-27"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19990330","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: 0

DNA hydration studied by neutron fiber diffraction. 中子纤维衍射法研究DNA水合作用。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_30

W Fuller, V T Forsyth, A Mahendrasingam, P Langan, W J Pigram, S A Mason, C C Wilson

{"title":"DNA hydration studied by neutron fiber diffraction.","authors":"W Fuller, V T Forsyth, A Mahendrasingam, P Langan, W J Pigram, S A Mason, C C Wilson","doi":"10.1007/978-1-4615-5847-7_30","DOIUrl":"https://doi.org/10.1007/978-1-4615-5847-7_30","url":null,"abstract":"The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institut Laue-Langevin. Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformational transitions in the DNA double-helix.","PeriodicalId":8697,"journal":{"name":"Basic life sciences","volume":"64 ","pages":"345-58"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19988975","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: 6

In situ shape and distance measurements in neutron scattering and diffraction. 中子散射和衍射的原位形状和距离测量。

Basic life sciences Pub Date : 1996-01-01 DOI: 10.1007/978-1-4615-5847-7_33

S Fujiwara, R A Mendelson

引用次数: 1