İntegrin İnhibitör Cyclo (Arg-Gly-Asp-D-Phe-Val) Peptidinin Moleküler Yapısı ve Kenetlenme Analizi (original) (raw)
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Starting from the first crystal structure of the extracellular segment of the R v 3 integrin receptor with a cyclic RGD ligand bound to the active site, structural models for the interactions of known ligands with the R v 3 integrin receptor were generated by automated computational docking. The obtained complexes were evaluated for their consistency with structure-activity relationships and site-directed mutagenesis data. A comparison between the calculated interaction free energies and the experimental biological activities was also made. All the possible interactions of the investigated compounds at the active site and the probable ligand binding conformations provide an improved basis for structure-based rational ligand design. Additionally, our docking results allow a further validation and refinement of the pharmacophore model previously postulated by us.
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Biophysical Reviews
Integrins are cell receptors involved in several metabolic pathways often associated with cell proliferation. Some of these integrins are downregulated during human physical development, but when these integrins are overexpressed in adult humans, they can be associated with several diseases, such as cancer. Molecules that specifically bind to these integrins are useful for cancer detection, diagnosis, and treatment. This review focuses on the structures of integrin-peptidic ligand complexes to dissect how the binding occurs and the molecular basis of the specificity and affinity of these peptidic ligands. Understanding these interactions at the molecular level is fundamental to be able to design new peptides that are more specific and more sensitive to a particular integrin. The integrin complexes covered in this review are α5β1, αIIbβ3, αvβ3, αvβ6, and αvβ8, because the molecular structures of the complex have been experimentally determined and their presence on tumor cancer cells ...
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induced binding sites; MCF, mean channel fl uorescence (equivalent of mean fl uorescence intensity); MCS, maximum common substructure; NIH MLSMR, NIH Molecular Libraries Small Molecule Repository; PDB, protein databank; VCAM-1, vascular cell adhesion molecule 1, CD106; VLA-4, very late antigen-4, CD49d/CD29, α 4 β 1 -integrin.
Biophysical Journal, 2002
It is well established that integrin ␣41 binds to the vascular cell adhesion molecule (VCAM) and fibronectin and plays an important role in signal transduction. Blocking the binding of VCAM to ␣41 is thought to be a way of controlling a number of disease processes. To better understand how various inhibitors might block the interaction of VCAM and fibronectin with ␣41, we began constructing a structure model for the integrin ␣41 complex. As the first step, we have built a homology model of the 1 subunit based on the I domain of the integrin CD11B subunit. The model, including a bound Mg 2ϩ ion, was optimized through a specially designed relaxation scheme involving restrained minimization and dynamics steps. The native ligand VCAM and two highly active small molecules (TBC772 and TBC3486) shown to inhibit binding of CS-1 and VCAM to ␣41 were docked into the active site of the refined model. Results from the binding analysis fit well with a pharmacophore model that was independently derived from active analog studies. A critical examination of residues in the binding site and analysis of docked ligands that are both potent and selective led to the proposal of a mechanism for 1/7 ligand binding selectivity.
International Journal of Molecular Sciences
The αvβ3 integrin, a receptor for many extracellular matrix proteins with RGD-sequence motif, is involved in multiple physiological processes and highly expressed in tumor cells, therefore making it a target for cancer therapy and tumor imaging. Several RGD-containing cyclic octapeptide (named LXW analogs) were screened as αvβ3 antagonists with dramatically different binding affinity, and their structure–activity relationship (SAR) remains elusive. We performed systematic SAR studies and optimized LXW analogs to improve antagonistic potency. The NMR structure of LXW64 was determined and docked to the integrin. Structural comparison and docking studies suggested that the hydrophobicity and aromaticity of the X7 amino acid are highly important for LXW analogs binding to the integrin, a potential hydrophobic pocket on the integrin surface was proposed to play a role in stabilizing the peptide binding. To develop a cost-efficient and fast screening method, computational docking was perf...
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Current Protein & Peptide Science, 2005
Peptides based on the amino acid sequences found at protein-protein interaction sites make excellent leads for antagonist development. A statistical picture of amino acids involved in protein-protein interactions indicates that proteins recognize and interact with one another through the restricted set of specialized interface amino acid residues, Pro, Ile, Tyr, Trp, Asp and Arg. These amino acids represent residues from each of the three classes of amino acids, hydrophobic, aromatic and charged, with one anionic and one cationic residue at neutral pH. The use of peptides as drug leads has been successfully used to search for antagonists of cell-surface receptors. Peptide, peptidomimetic, and non-peptide organic inhibitors of a class of cell surface receptors, the integrins, currently serve as therapeutic and diagnostic imaging agents. In this review, we discuss the structural features of proteinprotein interactions as well as the design of peptides, peptidomimetics, and small organic molecules for the inhibition of protein-protein interactions. Information gained from studying inhibitors of integrin functions is now being applied to the design and testing of inhibitors of other protein-protein interactions. Most drug development progress in the past several decades has been made using the enzyme binding-pocket model of drug targets. Small molecules are designed to fit into the substrate-binding pockets of proteins based on a lock-and-key, induced-fit, or conformational ensemble model of the protein binding site. Traditionally, enzymes have been used as therapeutic drug targets because it was easier to develop rapid, sensitive screening assays, and to find low molecular weight inhibitors that blocked the active site. However, for proteins which interact with other proteins, rather than with small substrate molecules, the lack of binding pockets means that this approach will not generally succeed. There exist many diseases in which the inhibition of protein-protein interactions would provide therapeutic benefit, but there are no general methods available to address such problems. The focus of the first part of this review is to discuss the features of protein-protein interactions which may serve as general guidelines for the development and design of inhibitors for protein-protein interactions. In the second part we focus on the design of peptides (lead compounds) and their conversion into peptidomimetics or small organic molecules for the inhibition of protein-protein interactions. We draw examples from the important and emerging area of integrin-based cell adhesion and show how the principles of protein-protein interactions are followed in the discovery, optimization and usage of specific protein interface peptides as drug leads.
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Integrins are transmembrane receptors that play a critical role in many biological processes which can be therapeutically modulated using integrin blockers, such as peptidomimetic ligands. This work aimed to develop new potential β1 integrin antagonists using modeled receptors based on the aligned crystallographic structures and docked with three lead compounds (BIO1211, BIO5192, and TCS2314), widely known as α4β1 antagonists. Lead-compound complex optimization was performed by keeping intact the carboxylate moiety of the ligand, adding substituents in two other regions of the molecule to increase the affinity with the target. Additionally, pharmacokinetic predictions were performed for the ten best ligands generated, with the lowest docking interaction energy obtained for α4β1 and BIO5192. Results revealed an essential salt bridge between the BIO5192 carboxylate group and the Mg2+ MIDAS ion of the integrin. We then generated more than 200 new BIO5192 derivatives, some with a greate...
Asian Journal of Pharmaceutical and Clinical Research
Objective: Cancer is the major worldwide problem. It arises due to uncontrolled growth of cells. In the present study a series of novel coumarin derivatives were designed and computationallyoptimized to investigate the interaction between designed ligands and 10 pdb files of five selected proteins. The objective here was to analyse in silico anticancerous activity of designed ligands to reduce cost and time for getting novel anticancerous drug with minimum side effects.Methods: Docking studies were performed to find outmaximum interaction between designed ligands and selected five proteins using Schrondinger software Maestro. Capecitabin has been used as reference compound. Structures of selected proteins were downloaded from protein data bank.Results: All the designed ligands showed mild to excellent binding with proteins.Most of the ligands exhibited better interaction compared to reference compoundcapacitabin with all pdb files. Some of designed ligands amongst (1-7) showe...