Estimating binding free energy of a putative growth factors EGF–VEGF complex – a computational bioanalytical study

<p>Epidermal growth factor (EGF) and homodimeric vascular endothelial growth factor (VEGF) bind to cell surface receptors. They are responsible for cell growth and angiogenesis, respectively. Docking of the individual proteins as monomeric units using ZDOCK 2.3.2 reveals a partial blocking of the receptor binding site of VEGF by EGF. The receptor binding site of EGF is not affected by VEGF. The calculated binding energy is found to be intermediate between the binding energies calculated for Alzheimer’s Aß42 and the barnase/barstar complex.</p

Membrane undulation induced by NS4A of Dengue virus: a molecular dynamics simulation study

<div><p>Nonstructural protein 4A (NS4A) of Dengue virus (DENV) is a membrane protein involved in rearrangements of the endoplasmic reticulum membrane that are required for formation of replication vesicles. NS4A is composed most likely of three membrane domains. The N- and C-terminal domains are supposed to traverse the lipid membrane whereas the central one is thought to reside on the membrane surface, thus forming a <i>u</i>-shaped protein. All three membrane domains are proposed to be helical by secondary structure prediction programs. After performing multi nanosecond molecular dynamics (MD) simulations at various temperatures (300, 310, and 315.15 K) with each of the individual domains, they are used in a docking approach to define putative association motifs of the transmembrane domains (TMDs). Two structures of the <i>u</i>-shaped protein are generated by separating two assembled TMDs linking them with the membrane-attached domain. Lipid undulation is monitored with the structures embedded in a fully hydrated lipid bilayer applying multiple 200 ns MD simulations at 310 K. An intact structure of the protein supports membrane undulation. The strong unwinding of the helices in the domain-linking section of one of the structures lowers its capability to induce membrane curvature. Unwinding of the link region is due to interactions of two tryptophan residues, Trp-96 and 104. These results provide first insights into the membrane-altering properties of DENV NS4A.</p></div

Development and Characterization of the Recombinant Human VEGF-EGF Dual-Targeting Fusion Protein as a Drug Delivery System

The design, preparation, as well as structural and functional characterizations of the recombinant fusion protein hVEGF-EGF as a dual-functional agent that may target both EGFR (R: receptor) and angiogenesis are reported. hVEGF-EGF was found to bind to EGFR more strongly than did EGF, and to bind to VEGFR similarly to VEGF. Mass spectrometry measurements showed that the sites of DTPA (diethylenetriaminepentaacetic acid) conjugated hVEGF-EGF (for radiolabeling) were the same as those of its parent hEGF and hVEGF proteins. All DTPA-conjugated proteins retained similar binding capacities to their respective receptors as compared to their respective parent proteins. In vitro cell binding studies using BAEC (a bovine aortic endothelial cell) and MDA-MB-231 (a human breast cancer) cells expressing both EGFR and VEGFR confirmed similar results. Treating BAEC cells with hVEGF-EGF induced remarkable phosphorylation of EGFR, VEGFR, and their downstream targets ERK1/2. Nevertheless, the radiolabeled ¹¹¹In-DTPA-hVEGF-EGF showed cytotoxicity against MDA-MB-231 cells. Pharmacokinetic studies using ¹¹¹In-DTPA-hVEGF-EGF in BALB/c nude mice showed that appreciable tracer activities were accumulated in liver and spleen. In all, this study demonstrated that the fusion protein hVEGF-EGF maintained the biological specificity toward both EGFR and VEGFR and may be a potential candidate as a dual-targeting moiety in developing anticancer drugs