Somatostatin analogs. Relative importance of the disulfide bridge and of the Ala-Gly side chain for biological activity

1975 ◽  
Vol 18 (2) ◽  
pp. 123-126 ◽  
Author(s):  
J. Rivier ◽  
P. Brazeau ◽  
W. Vale ◽  
R. Guillemin
Keyword(s):  
Biological Activity ◽  
Somatostatin Analogs ◽  
Disulfide Bridge ◽  
Side Chain ◽  
Relative Importance

Replacement of the interchain disulfide bridge-forming amino acids A7 and B7 by glutamate impairs the structure and activity of insulin

2004 ◽  
Vol 385 (12) ◽  
pp. 1171-1175 ◽  
Author(s):  
Zhan-Yun Guo ◽  
Xiao-Yuan Jia ◽  
You-Min Feng
Keyword(s):  
Biological Activity ◽  
Disulfide Bonds ◽  
Negative Charge ◽  
Disulfide Bridge ◽  
Site Directed Mutagenesis ◽  
Side Chain ◽  
Insulin Analogs ◽  
High Biological Activity ◽  
Chemical Groups ◽  
Structure And Activity

Abstract Insulin contains three disulfide bonds, one intrachain bond, A6–A11, and two interchain bonds, A7–B7 and A20–B19. Site-directed mutagenesis results (the two cysteine residues of disulfide A7–B7 were replaced by serine) showed that disulfide A7–B7 is crucial to both the structure and activity of insulin. However, chemical modification results showed that the insulin analogs still retained relatively high biological activity when A7Cys and B7Cys were modified by chemical groups with a negative charge. Did the negative charge of the modification groups restore the loss of activity and/or the disturbance of structure of these insulin analogs caused by deletion of disulfide A7–B7? To answer this question, an insulin analog with both A7Cys and B7Cys replaced by Glu, which has a long side-chain and a negative charge, was prepared by protein engineering, and its structure and activity were analyzed. Both the structure and activity of the present analog are very similar to that of the mutant with disulfide A7–B7 replaced by Ser, but significantly different from that of wild-type insulin. The present results suggest that removal of disulfide A7–B7 will result in serious loss of biological activity and the native conformation of insulin, even if the disulfide is replaced by residues with a negative charge.

scholarly journals Synthesis and Biological Activity of Brassinosteroid Analogues with a Nitrogen-Containing Side Chain

2020 ◽  
Vol 22 (1) ◽  
pp. 155
Author(s):  
Mikhail V. Diachkov ◽  
Karoll Ferrer ◽  
Jana Oklestkova ◽  
Lucie Rarova ◽  
Vaclav Bazgier ◽  
...  
Keyword(s):  
Biological Activity ◽  
Functional Groups ◽  
Side Chain ◽  
Biotic And Abiotic Stresses ◽  
Short Side ◽  
Arabidopsis Root ◽  
Physiological Processes ◽  
Growth Promoting ◽  
The Impact ◽  
Brassinosteroid Analogues

Brassinosteroids are a class of plant hormones that regulate a broad range of physiological processes such as plant growth, development and immunity, including the suppression of biotic and abiotic stresses. In this paper, we report the synthesis of new brassinosteroid analogues with a nitrogen-containing side chain and their biological activity on Arabidopis thaliana. Based on molecular docking experiments, two groups of brassinosteroid analogues were prepared with short and long side chains in order to study the impact of side chain length on plants. The derivatives with a short side chain were prepared with amide, amine and ammonium functional groups. The derivatives with a long side chain were synthesized using amide and ammonium functional groups. A total of 25 new brassinosteroid analogues were prepared. All 25 compounds were tested in an Arabidopsis root sensitivity bioassay and cytotoxicity screening. The synthesized substances showed no significant inhibitory activity compared to natural 24-epibrassinolide. In contrast, in low concentration, several compounds (8a, 8b, 8e, 16e, 22a and 22e) showed interesting growth-promoting activity. The cytotoxicity assay showed no toxicity of the prepared compounds on cancer and normal cell lines.

scholarly journals Relationship of 25-hydroxyvitamin D3 side chain structure to biological activity.

1975 ◽  
Vol 250 (1) ◽  
pp. 226-230
Author(s):  
M F Holick ◽  
M Garabedian ◽  
H K Schnoes ◽  
H F DeLuca
Keyword(s):  
Biological Activity ◽  
Chain Structure ◽  
Side Chain ◽  
Relationship Of

scholarly journals Arsenoplatin-Ferritin Nanocage: Structure and Cytotoxicity

2021 ◽  
Vol 22 (4) ◽  
pp. 1874
Author(s):  
Giarita Ferraro ◽  
Alessandro Pratesi ◽  
Damiano Cirri ◽  
Paola Imbimbo ◽  
Daria Maria Monti ◽  
...  
Keyword(s):  
Biological Activity ◽  
Diffraction Data ◽  
Inductively Coupled Plasma ◽  
Emission Spectroscopy ◽  
Atomic Emission ◽  
Side Chain ◽  
Plasma Atomic Emission ◽  
Average Amount ◽  
X Ray ◽  
Inductively Coupled

Arsenoplatin-1 (AP-1), the prototype of a novel class of metallodrugs containing a PtAs(OH)2 core, was encapsulated within the apoferritin (AFt) nanocage. UV-Vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy measurements confirmed metallodrug encapsulation and allowed us to determine the average amount of AP-1 trapped inside the cage. The X-ray structure of AP-1-encapsulated AFt was solved at 1.50 Å. Diffraction data revealed that an AP-1 fragment coordinates the side chain of a His residue. The biological activity of AP-1-loaded AFt was comparatively tested on a few representative cancer and non-cancer cell lines. Even though the presence of the cage reduces the overall cytotoxicity of AP-1, it improves its selectivity towards cancer cells.

Synthesis and biological activity of branched enkephalin analogues containing two amino acids in a side chain

1998 ◽  
Vol 33 (4) ◽  
pp. 331-334 ◽  
Author(s):  
Irina Bobrova ◽  
Natalia Mishlakova ◽  
Anette Selander ◽  
Elena Mekshun ◽  
Guntis Rozental
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Side Chain ◽  
Enkephalin Analogues

Hashish. 16. Unsaturated side-chain analogs of .DELTA.8-tetrahydrocannabinol with potent biological activity

1976 ◽  
Vol 19 (11) ◽  
pp. 1328-1330 ◽  
Author(s):  
Raj K. Razdan ◽  
Haldean C. Dalzell ◽  
Patricia Herlihy ◽  
John F. Howes
Keyword(s):  
Biological Activity ◽  
Side Chain

Transforming growth factor alpha: an aromatic side chain at position 38 is essential for biological activity

1989 ◽  
Vol 9 (2) ◽  
pp. 860-864
Author(s):  
E Lazar ◽  
E Vicenzi ◽  
E Van Obberghen-Schilling ◽  
B Wolff ◽  
S Dalton ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Disulfide Bonds ◽  
Transforming Growth Factor ◽  
Site Directed Mutagenesis ◽  
Side Chain ◽  
Transforming Growth Factor Alpha ◽  
Aromatic Side Chain ◽  
Factor Alpha ◽  
Alpha Gene

Site-directed mutagenesis has been performed in the human transforming growth factor alpha gene. When tyrosine 38 is mutated into phenylalanine or tryptophane, biological activity is retained. In contrast, other alterations between cysteine 34 and cysteine 43 and disruption of disulfide bonds 8 to 21 and 34 to 43 resulted in loss of activities. The presence of an aromatic side chain at position 38 of transforming growth factor alpha seems to be essential for its activity.

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