ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Structural basis of chaperone–subunit complex recognition by the type 1 pilus assembly platform FimD (2005)
    EMBO Press
    Details
    Publication Date: 2005-05-26
    Print ISSN: 0261-4189
    Electronic ISSN: 1460-2075
    Topics: Biology , Medicine
    Published by EMBO Press on behalf of European Molecular Biology Organization.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    NMR structure of the bovine prion protein isolated from healthy calf brains (2004)
    EMBO Press
    Details
    Publication Date: 2004-12-01
    Print ISSN: 1469-221X
    Electronic ISSN: 1469-3178
    Topics: Biology , Medicine
    Published by EMBO Press on behalf of European Molecular Biology Organization.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    Electronic Resource
    Electronic Resource
    The X-Pro peptide bond as an nmr probe for conformational studies of flexible linear peptides (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2025-2041 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The equilibrium between the cis and trans forms of X-Pro peptide bonds can readily be measured in the 13C nmr spectra. In the present paper we investigate how observation of this equilibrium could be used as an nmr probe for conformational studies of flexible polypeptide chains. The experiments include studies by 13C nmr of a series of linear oligopeptides containing different X-L-Pro peptide bonds, with X = Gly, L-Ala, L-Leu, L-Phe, D-Ala, D-Leu, and D-Phe. Overall the study confirms that X-Pro peptide bonds can generally be useful as 13C nmr probes reporting the formation of nonrandom conformation in flexible polypeptide chains. It was found that the cis-trans equilibrium of X-Pro is greatly affected by the side chain of X and the configuration of the α-carbon atom of X. On the basis of these observations some general rules are suggested for a practical applications of the X-Pro nmr probes in conformational studies of polypeptide chains.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1976.360151012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Nmr studies of the molecular conformations in the linear oligopeptides H-(L-Ala)n-L-Pro-OH (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2043-2057 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular conformations of the linear oligopeptides H-(L-Ala)n-L-Pro-OH, with n = 1,2 and 3, have been investigated. 13C nmr observation of the equilibrium between the cis and trans forms of the Ala-Pro peptide bond indicated the occurrence of nonrandom conformations in solutions of these flexible peptides. The formation of the nonrandom species containing the cis form of the Ala-Pro bond was found to depend on the deprotonation of the carboxylic acid group of proline, the solvent, and the ionic strength in aqueous solution. The influence of intramolecular hydrogen bonding on the relative conformational energies of the species containing the cis and trans Ala-Pro peptide bond was studied by comparison of the peptides H-(Ala)n-Pro-OH with analogous molecules where hydrogen bond formation was excluded by the covalent structure. In earlier work a hydrogen bond between the protonated terminal carboxylic acid group and the carbonyl oxygen of the penultimate amino acid residue had been suggested to stabilize conformations including trans proline. For the systems described here this hypothesis can be ruled out, since the cis:trans ratio is identical for molecules with methyl ester protected and free protonated terminal carboxylic acid groups of proline. Direct evidence for hydrogen bond formation between the deprotonated terminal carboxylic acid group and the amide proton of the penultimate amino acid residue in the molecular species containing cis proline was obtained from 1H nmr studies. However, the cis:trans ratio of the Ala-Pro bond was not affected by N-methylation of the penultimate amino acid residue, which prevents formation of this hydrogen bond. Overall the experimental observations lead to the conclusion that the relative energies of the peptide conformations including cis or trans proline are mainly determined by intramolecular electrostatic interactions, whereas in the molecules considered, intramolecular hydrogen bonding is a consequence of specific peptide backbone conformations rather than a cause for the occurrence of energetically favored species. Independent support for this conclusion was obtained from model consideration which indicated that electrostatic interactions between the terminal carboxylic acid group and the carbonyl oxygen of the penultimate amino acid residue could indeed account for the observed relative conformational energies of the species containing cis and trans proline, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1976.360151013
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    1H-nmr parameters of the common amino acid residues measured in aqueous solutions of the linear tetrapeptides H-Gly-Gly-X-L-Ala-OH (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 285-297 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H-nmr chemical shifts and the spin-spin coupling constants of the common amino acid residues were measured in solutions of the linear tetrapeptides H-Gly-Gly-X-L-Ala-OH in D2O and H2O, the influence of X on the nmr parameters of the neighboring residues Gly 2 and Ala 4 was investigated. The titration parameters for the side chains of Asp, Glu, Lys, Tyr, and His were determined. The pKa values obtained in D2O, with the use of pH-meter readings with a combination glass electrode uncorrected for istope effects, were 0.06 pH units higher in the acidic range and 0.10 pH units higher in the basic range than the corresponding pKa values in H2O. This suggests that the present data are suitable “random-coil” 1H-nmr parameters for conformational studies of polypeptide chains in D2O and H2O solutions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Use of amide 1H-nmr titration shifts for studies of polypeptide conformation (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 299-311 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper shows that backbone amide proton titration shifts in polypeptide chains are a very sensitive manifestation of intramolecular hydrogen bonding between carboxylate groups and backbone amide protons. The population of specific hydrogen-bonded structures in the ensemble of species that constitutes the conformation of a flexible nonglobular linear peptide can be determined from the extent of the titration shifts. As an illustration, an investigation of the molecular conformation of the linear peptide H-Gly-Gly-L-Glu-L-Ala-OH is described. The proposed use of amide proton titration shifts for investigating polypeptide conformation is based on 360-MHz 1H-nmr studies of selected linear oligopeptides in H2O solutions. It was found that only a very limited number of amide protons in a polypeptide chain show sizable intrinsic intration shifts arising from through-bond interactions with ionizable groups. These are the amide proton of the C-terminal amino acid residue, the amide protons of Asp and the residues following Asp, and possibly the amide proton of the residue next to the N-terminus. Since the intrinsic titration shifts are upfield, the downfield titration shifts arising from conformation-dependent through-space interactions, in particular hydrogen bonding between the amide protons and carboxylate groups, can readily be identified.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Conformational energy studies of linear dipeptides H-X-L-Pro-OH (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 2589-2606 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Empirical conformational energy calculations with the use of ECEPP energy functions have been carried out for linear dipeptides H-X-L-Pro-OH, with X = Gly, L-Ala, D-Ala, L-Leu, D-Leu, L-Phe, and D-Phe, in different states of protonation of the end groups. The results of these calculations are compared with the previously reported experimental equilibrium populations for the cis and trans isomers of the X-Pro bond in the different species. For all the protonation states of the seven dipeptides, the calculated nonbonded interactions and the conformational entropy term lead to a preference of the trans forms over the cis isomers by at least 1 kcal/mol. The electrostatic interactions stabilize the cis conformations in all species except the cationic forms of the D,L-peptides, and it could further be shown that only the carbonyl group of X and the two end groups contribute significantly to the total electrostatic energy. One of the principal results of the experimental studies, i.e., the occurrence of 5-15% cis-proline in all the peptides with an uncharged C-terminus, was corroborated by our investigation of the cationic species. A detailed assessment of the electrostatic contribution to the total energy of the different conformations of H-Gly-L-Pro-OH indicates that the standard ECEPP parameters tend to overestimate the electrostatic interactions in aqueous solutions of the X-Pro dipeptides.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360181015
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Analysis of the 1H-NMR spectra of ferrichrome peptides. II. The amide resonances (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 2911-2911 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360181119
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Nmr studies of the rates of proline cis-trans isomerization in oligopeptides (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 2623-2633 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H-Nmr was used to measure the rate of cis-trans interconversion of X-Pro bonds in linear and cyclic oligopeptides. k(cis → trans) = 2.5 × 10-3 s-1 at 25°C was found for the zwitterionic form of H-Ala-Pro-OH, in good agreement with earlier measurements. Replacement of Ala by Phe, Tyr, or Trp resulted in a 10-fold slower interconversion rate, whereas after substitution of Ala by His or Glu, the rate decreased only slightly. Independent of the residues X, the interconversion rate was increased by a factor of ca. 20 when the peptide chain was elongated by addition of Ala to the C-terminal Pro. An additional increase by a factor of 6 was observed when going from the protected linear peptide CF3CO-Gly-Gly-Pro-Ala-OCH3 to the closely related cyclic compound c[-Gly-Gly-Pro-Gly-Ala-]. These data are evaluated with regard to their possible use in future studies on the role of X-Pro cis-trans isomerization in the kinetics of protein folding.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360201209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The program FANTOM for energy refinement of polypeptides and proteins using a Newton - Raphson minimizer in torsion angle space (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 679-694 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The program FANTOM (fast Newton-Raphson torsion angle energy minimizer) performs minimizations of the ECEPP/2 energy function for proteins with the Newton-Raphson method. It is implemented for use with conventional computer hardware. The torsion angles are chosen as independent variables. The first and second derivatives are calculated with a previously described rapid algorithm. For the matrix inversion a modified Cholesky factorization is used. A line search adjusts the step length and nonbonded interactions can be calculated with a cutoff. The following tests of the program are described: All local minima of the ECEPP/2 energy function for the amino acids glycine and alanine were determined. An exhaustive search by more than 16,000 independent energy minimizations was used to identify low-energy structures of Met-enkephalin, which were then compared with previously published structures of this pentapeptide. To investigate the use of FANTOM with disulfide bonds, it was applied with conotoxin. As an illustration of the intended primary use of the program, an energy refinement of the structure of the basic pancreatic trypsin inhibitor determined by nmr spectroscopy in solution is described.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360290403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...