Title
The antiangiogenic and antitumor activities of the N-terminal fragment of endostatin augmented by Ile/Arg substitution: The overall structure implicated the biological activity
Author
Reyhane Chamani, S. Mohsen Asghari, Ali Mohammad Alizadeh, Kamran Mansouri, Taher Doroudi, Peir Hossein Kolivand, Hossein Ghafouri, Somayeh Ehtesham, Hanieh Rabouti, Faramarz Mehrnejad
Year
2016
Journal
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Abstract
The antiangiogenic and antitumor activities of the 27-amino acid fragment corresponding to the N-terminal domain of endostatin were shown to be dependent on a Zn-binding loop in the N-terminus. To investigate whether the regions outside of the N-terminal loop play a role in the peptide function, the structure and function of a variant containing Ile26Arg mutation (ES-R) were compared with those of the native peptide (ES-Zn). Structural analysis using far-UV CD, intrinsic fluorescence and molecular dynamics simulation provided information regarding the overall changes upon the mutation. In addition, the docking simulations predicted a higher affinity of ES-R to integrins αvβ3 and α5β1 than ES-Zn and a profound reorganization of the binding residues throughout the sequence. In Human Umbilical Vein Endothelial Cells (HUVECs), ES-R inhibited the tube formation and activated caspase-3 more strongly than do ES-Zn. Based on in vivo studies, the growth of breast tumor and expression of CD31, Bcl-2 and nonfunctional p53 were inhibited more effectively by ES-R than by ES-Zn. We conclude that the C-terminal region is involved in the peptide function through some global structural effects.
Instrument
J-715
Keywords
Circular dichroism, Secondary structure, Biochemistry