摘要:

AbstractThe complete sequential assignment and conformation of d‐GpCpGpC in D2O has been determined from ID NMR spectra at 285–320 K and room temperature 2D‐COSY and NOESY spectra. The tetradeoxynucleotide exists primarily as a right handed double helix at 285 K, havingTmas 314 K. On binding to a tripeptide Lys‐Tyr‐Lys in a concentration equimolar to tetranucleotide duplex, the Tyr ring protons shift uplifted by 0.14 ppm at 285 K. The increase inTmon binding suggests stabilization of duplex. The existence of intermolecular NOEs between C4 sugar protons and TyrαC and LysαC protons give direct evidence of proximity of Tyr residue to the C4 base of d‐GpCpGpC. The conformation of d‐GpCpGpC remains unchanged on binding. The observed results are interpreted in terms of preferential stacking of aromatic ring of Tyr residue with proximal base‐pair of d‐GpCpGpC, stabilized by electostatic interaction of Lysine side chains with backbone phosphates. This is in contrast to intercalculation of aromatic dyes within base‐pairs resulting in a change in sugar conformatio

ISSN:0952-3499    

DOI:10.1002/jmr.300040202

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe non‐coding strand of the bombesin receptor gene, when ‘translated’ 5′ 3′, contains and interrupted sequence of the 10 amino acids of bombesin. This finding forms the basis for proposing the points of contact between bombesin and its receptor as well as a partial conformation of the binding region of the receptor as well as partial conformation of the binding region of the

ISSN:0952-3499    

DOI:10.1002/jmr.300040203

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractAlthough the rules which describes the atomic basis of structure–function relationships of proteins have yet to be deciphered, they are nevertheless coded within the framework of the amino acid and nucleotide sequence. The objectives of the present investigations were to document a composite, new approach for the evaluation of the structure–function dependencies of proteins based on the analysis of the informational content of the primary amino acid sequence as well as the topological and functional regions of a protein. This approach is validated with the example of the p21 Ha‐ras oncogene family of proteins. Using this approach is validated with the example of the p21 Ha‐ras oncogene family of proteins. Using this approach, amino acids crucial for p21 transforming activity have been identified and these amino acid residue assignments compared with experiment

ISSN:0952-3499    

DOI:10.1002/jmr.300040204

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe amino acid sequences of human and murine haemopoietins have been analysed using algorithms predictive for secondary structure. The results for 19 of these proteins (human and murine Interleukins 2, 3, 4, 5, 6, 7 and granulocyte, macrophage and granulocyte macrophage‐colony stimulating factors as well as human erythropoietin) suggest that they each contain a 4‐α‐helical bundle, ca 25 Å long, as a common conformational feature. The most important predictive indicator was considered to be occurrence of quasi‐repeating sequences of seven amino acids of the form (a‐b‐c‐d‐e‐f‐g)nwith a polar side chains (usually leucine) lying alternately three and four residues apart in theaanddpositions. As with other proteins of known secondary structure this periodicity favors the formation of α‐helical elements, each with an a polar external strip, which interdigitate closely with one another when tested appropriately. Molecular models based on these putative 4‐α‐helical bundles are presented – with special references to human granulocyte macrophage‐colony stimulating factor. The extent to which such models are consistent with experiments designed to delineate re

ISSN:0952-3499    

DOI:10.1002/jmr.300040205

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractCitrate synthase (EC 4.1.3.7), which is present in all living organisms as a key enzyme in aerobic energy metabolism, is one of the most highly phylogenetically conserved enzymes known in terms of its primary and active site structure. However, in terms of other parameters such asin vitrostability, tolerance to changes in pH, degree of self‐polymerization, etc., citrate syntheses different sources are markedly different. These divergences can be observed even between isoforms of the enzyme within the same species. Data documenting these diversities suggest that a high degree of difference in tertiary structures may occur. Therefore, the surface profiles of citrate synthase enzymes from yeast, pig, rat, tomato andEscherichia coliwere investigated with immunological methods using monoclonal antibody families generated against either pig citrate synthase (α‐PCS) or yeast citrate synthase‐2 (α‐YCS‐2). A high degree of homology of enzyme epitopes was detected on the mitochondrial citrate synthases originating from yeast, tomato, pig and rat cells. Major differences were found between the hexameric citrate synthase originating fromE. colicompared with those dimeric forms prepared from eukaryotic cells. Only modest similarities were detected between the highly homologous peroxisomal and mitochondrial yeast citrate syntheses. Furthermore, a point mutation of one of the catalytic residues (H274R on recombinant pig and H313R on yeast enzyme) of mitochondrial citrate synthase (CS‐1) resulted in a significant increase in immunological similarity with the peroxisomal isoenzyme (CS‐2). These findings are discussed in terms of the possible mechanism of evolution o

ISSN:0952-3499    

DOI:10.1002/jmr.300040206

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo polyclonal antibodies were raised by immunizing rabbits with two non carrier‐linked synthetic peptides whose amino acid sequences corresponded to codons 89–107 (peptide P1) and 219–233 (peptide P2) of the translated cDNA sequence of murine PrP protein. These free peptides, whose structural characteristics in solution were studied by circular dichroism, elicited a reasonable immunologic response in animals. Both antibodies still recognized the corresponding immunogens after affinity chromatography purification. However, only antibodies raised to the former sequence reacted by immunobolt with a purified preparation of murine scrapie amyloid protein. These findings are discussed together with their correlation to peptide structure and the effectiveness of this simplified immunization proc

ISSN:0952-3499    

DOI:10.1002/jmr.300040207

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractA method is proposed for the selection of experimental conditions for sedimentation equilibrium experiments that will provide maximal information about the values of equilibrium association constants within a given scheme for heteroassociation of two solute components. A discriminator function is proposed that indicates the sensitivity of the experimentally observed gradient or gradients to alternations in the underlying association constants. The value of this function is plotted or tabulated as a function of the concentrations of the two components, over a broad range of solution compositions. It is suggested that experiments performed with loadings compositions corresponding to large absolute values of the discriminator function will yield the most information with respect to determination of the underlying association constants. This method was tested by predicting optimal conditions for three different types of sedimentation equilibrium experiments: (i) measurement of total (natural) solute absorbance; (ii) measurement of individual component gradients via measurement of tracer absorbance; and (iii) global analysis of multiple experiments. Experimental data resulting from sedimentation equilibrium experiments carried out under the specified conditions were simulated by addition of realistic levels of random error to calculated equilibrium gradients. The simulated data were then analyzed exactly as real experimental data, i. e. without prior knowledge of the underlying association constants. It was found that the highest accuracy and precision in determination of heteroassociation constants are obtained by global analysis of multiple experiments performed using significantly different loading compositions, each of which is selected from ‘sensitive’ regions of the discriminator

ISSN:0952-3499    

DOI:10.1002/jmr.300040208

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0952-3499    

DOI:10.1002/jmr.300040209

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0952-3499    

DOI:10.1002/jmr.300040210

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0952-3499    

DOI:10.1002/jmr.300040201

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY