Synthesis and Biological Activities of New Conformationally Restricted Analogues of (−)-Indolactam-V:  Elucidation of the Biologically Active Conformation of the Tumor-Promoting Teleocidins

1996 ◽  
Vol 118 (44) ◽  
pp. 10733-10743 ◽  
Author(s):  
Kazuhiro Irie ◽  
Tomomi Isaka ◽  
Yoriko Iwata ◽  
Yoshiaki Yanai ◽  
Yoshimasa Nakamura ◽  
...  
Keyword(s):  
Biological Activities ◽  
Biologically Active ◽  
Active Conformation ◽  
Conformationally Restricted ◽  
Biologically Active Conformation

Analogues of the cholecystokinin octapeptide modified in the central part of the molecule

1991 ◽  
Vol 56 (9) ◽  
pp. 1963-1970 ◽  
Author(s):  
Jan Hlaváček ◽  
Václav Čeřovský ◽  
Jana Pírková ◽  
Pavel Majer ◽  
Lenka Maletínská ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Point Of View ◽  
Biologically Active ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cholecystokinin Octapeptide ◽  
Biological Tests ◽  
Biological Potency ◽  
Biologically Active Conformation

In a series of analogues of the cholecystokinin octapeptide (CCK-8) the amino acid residues were gradually modified by substituting Gly by Pro in position 4, Trp by His in position 5, Met by Cle in position 6, or the Gly residue was inserted between Tyr and Met in positions 2 and 3 of the peptide chain, and in the case of the cholecystokinin heptapeptide (CCK-7) the Met residues were substituted by Nle or Aib. These peptides were investigated from the point of view of their biological potency in the peripheral and central region. From the results of the biological tests it follows that the modifications carried out in these analogues and in their Nα-Boc derivatives mean a suppression of the investigated biological activities by 2-3 orders of magnitude (at a maximum dose of the tested substance of 2 . 10-2 mg per animal).This means that a disturbance of the assumed biologically active conformation of CCK-8, connected with a considerable decrease of the biological potency of the molecule, takes place not only after introduction of the side chain into its centre (substitution of Gly4), but also after the modification of the side chains of the amino acids or by extension of the backbone in further positions around this central amino acid.

The determination of thymopoietin conformation based on X-ray structure of a discontinuous thymopoietin-like motif of G-actin.

1997 ◽  
Vol 44 (3) ◽  
pp. 519-525
Author(s):  
I Z Siemion ◽  
I Strug ◽  
Z Szewczuk
Keyword(s):  
Biologically Active ◽  
Active Conformation ◽  
X Ray ◽  
Biologically Active Conformation

The biologically active conformation of thymopoietin, based on X-ray data reported for discontinuous thymopoietin-like motif of G-actin, is proposed. The conformation is compared with that resulting from the prediction made by the method of Chou & Fasman (Annu. Rev. Biochem. 47, 251-276, 1978) and Rost & Sander (Methods Enzymol. 266, 525-539, 1996).

scholarly journals Analysis of the code relating sequence to conformation in globular proteins. Theory and application of expected information

1974 ◽  
Vol 141 (3) ◽  
pp. 853-867 ◽  
Author(s):  
Barry Robson
Keyword(s):  
Information Theory ◽  
Theoretical Basis ◽  
Biologically Active ◽  
Active Conformation ◽  
Primary Sequence ◽  
Theory Analysis ◽  
Expected Information ◽  
Transfer Of Information ◽  
Algebraic Formulation ◽  
Biologically Active Conformation

1. An information theory analysis of the folding of a globular protein is proposed. 2. The folding is seen as a transfer of information between two messages, the primary sequence and the biologically active conformation. 3. It is shown how the information transferred was estimated by inspection of proteins of known primary sequence and conformation. 4. In this estimation, concerted use of subjective (Bayesian) probabilities leads to a more robust approach which can be employed whether the number of proteins of known sequence and conformation is large or small. 5. Further, it is demonstrated that the problem then becomes a very simple algebraic formulation for information estimates. 6. Finally, it is shown how this process of information theory analysis can be reversed to predict the conformation of a protein by using its primary sequence and the above information estimates obtained from other proteins. 7. The present paper provides the theoretical basis for the derivation and application of a stereochemical alphabet (Robson & Pain, 1974a,c), and for an investigation of the effects of residues on the conformations of their neighbours (Robson & Pain, 1974b).

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