ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    ISSN: 1075-2617
    Keywords: Hormone biosynthesis ; ocytocin ; prohormone ; proteolytic processing ; β-turn ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthetic peptides reproducing the proteolytic processing site of pro-ocytocin were studied by different spectroscopic techniques, including circular dichroism, Fourier tranform infrared absorption, and mono and bidimensional nuclear magnetic resonance, in order to ascertain the possible role of three-dimensional structure in the recognition process by maturation enzymes. Experimental results were compared with energy minimization calculations and suggest that: (i) the region situated on the N-terminus of the Lys-Arg doublet may form a β-turn; (ii) the sequential organization of the residues participating in the β-turn determines the privileged relative orientation of the basic amino acid sidechains and the subtype of turn; and (iii) the peptide segment situated on the C-terminal side of the dibasic doublet may assume a helix arrangement. These findings, in spite of the limitations connected to the flexibility of linear peptides, seem to substantiate the hypothesis that structural motifs around the cleavage site could be important for recognition and processing. However, a straightforward correlation between details of the secondary structure and the in vitro reactivity toward a putative convertase is not yet possible.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1075-2617
    Keywords: β-turn ; cyclic amino acid ; 310-helix ; peptide conformation ; X-ray diffraction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of N- and C-protected, monodispersed homo-oligopeptides (to the pentamer level) from the cycloaliphatic Cα,α,-dialkylated glycine 1-aminocyclononane-1-carboxylic acid (Ac9c) and two Ala/Ac9c tripeptides have been synthesized by solution methods and fully characterized. The conformational preferences of all the model peptides were determined in deuterochloroform solution by FT-IR absorption and 1H-NMR. The molecular structures of the amino acid derivatives mClAc-Ac9c-OH and Z-Ac9c-OtBu, the dipeptide pBrBz-(Ac9c)2-OtBu, the tetrapeptide Z-(Ac9c)4-OtBu, and the pentapeptide Z-( Ac9c)5-OtBu were determined in the crystal state by X-ray diffraction. Based on this information, the average geometry and the preferred conformation for the cyclononyl moiety of the Ac9c residue have been assessed. The backbone conformational data are strongly in favour of the conclusion that the Ac9c residue is a strong β-turn and helix former. A comparison with the structural propensity of α-aminoisobutyric acid, the prototype of Cα,α-dialkylated glycines, and the other extensively investigated members of the family of 1-aminocycloalkane-1-carboxylic acids (Acnc, with n=3-8) is made and the implications for the use of the Ac9c residue in conformationally constrained analogues of bioactive peptides are briefly examined. © 1997 European Peptide Society and John Wiley & Sons, Ltd.J. Pep. Sci. 3: 367-382No. of Figures: 10. No. of Tables: 6. No. of References: 62
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0006-3525
    Keywords: molecular scaffolds ; β-turn ; tachykinin antagonist ; x-ray ; nmr ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We recently reported the rational design, synthesis, and structural characterization of the most potent and selective peptide-based neurokinin A antagonist thus far described: cyclo(Met1-Asp2-Trp3-Phe4-Dap5-Leu6)cyclo(2β-5β). Its bicyclic structure is characterized by a type I and a type II two β-turn around Trp3-Phe4 and Leu6-Met1, respectively. In order to understand whether the two different β-turned structures are determined by the bicyclic structure or by the amino acid type at the corner positions, we have synthesized the pseudosymmetrical analogue cyclo(Phe1-Asp2-Trp3-Phe4-Dap5-Trp6)cyclo(2β-5β). The structural characterization in the crystal state and in solution, here reported, gives an experimental evidence that the backbone of the bicyclic structure is a rigid scaffold that can be used to build both a type I and type II β-turn independently from the amino acid composition. © 1997 John Wiley & Sons, Inc. Biopoly 40: 505-518, 1996
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0006-3525
    Keywords: cyclic peptides ; molecular dynamics ; nmr ; conformation ; FK506 ; FK506 binding proteins ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational behavior in solution of a cyclic peptide with sequence cyclo-(Pro1-Pro2-Dab3 (cHexA)ψ[N7HCO]-Leu4ψ[NHCO]-Suc5-Gly6-) has been throughly investigated with the combined use of nmr and molecular dynamic techniques. The compound, which has been modeled to mimic the FK506 macrolide bound to the FK506 binding protein structure, can be considered as a peptidic analogue of the FK506 system.The synthesis was carried out on a phenylacetoamidomethyl resin using an appropriate protocol for the peptide chain elongation. The conformational properties of the cyclic hexapeptide were studied in DMSO and water. The nmr data in DMSO and restrained molecular dynamics simulations show the presence of two contiguous cis peptide bonds involving the -Gly-Pro-Pro- segment. This segment in water exhibits conformational heterogeneity presenting at least two distinct conformational families, characterized the first by cis-cis and the second by a trans-cis Gly-Pro-Pro configuration; the trans-cis isomer was fully characterized. © 1997 John Wiley & Sons, Inc. Biopoly 42: 349-361, 1997
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0006-3525
    Keywords: cyclic decapeptides ; cyclolinopeptide A ; x-ray ; nmr ; conformation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational analysis of synthetic cyclodecapeptide c(Pro-Phe-Phe-Aib-Leu)2 related to the cyclolinopeptide A, in the solid state and solution, has been carried out by x-ray diffraction and nmr spectroscopy. The structure of the monoclinic form obtained from methanol [a = 11.351(5) Å, b = 27.455(2) Å, c = 12.716(8) Å, β = 99.65(3)°; space group P21; Z = 2] shows the presence of six intramolecular NH···CO hydrogen bonds, with formation of four turns (three of type I and one of type III) and two C16 ring structures. All peptide units are trans. The solution structure, as found by nmr, indicates that, at room temperature, the peptide is conformationally homogeneous; the structure determined is perfectly symmetrical and topologically similar to that found in the solid state. The cyclodecapeptide exhibits similar biological activity to cyclolinopeptide A. © 1997 John Wiley & Sons, Inc. Biopoly 40: 465-478, 1996
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...