Protecting role of cosolvents in protein denaturation by SDS: a structural study

<p>Abstract</p> <p>Background</p> <p>Recently, we reported a unique approach to preserve the activity of some proteins in the presence of the denaturing agent, Sodium Dodecyl Sulfate (SDS). This was made possible by addition of the amphipathic solvent 2,4-Methyl-2-PentaneDiol (MPD), used as protecting but also as refolding agent for these proteins. Although the persistence of the protein activity in the SDS/MPD mixture was clearly established, preservation of their structure was only speculative until now.</p> <p>Results</p> <p>In this paper, a detailed X-ray study addresses the pending question. Crystals of hen egg-white lysozyme were grown for the first time in the presence of MPD and denaturing concentrations of SDS. Depending on crystallization conditions, tetragonal crystals in complex with either SDS or MPD were collected. The conformation of both structures was very similar to the native lysozyme and the obtained complexes of SDS-lysozyme and MPD-lysozyme give some insights in the interplay of protein-SDS and protein-MPD interactions.</p> <p>Conclusion</p> <p>This study clearly established the preservation of the enzyme structure in a SDS/MPD mixture. It is hypothesized that high concentrations of MPD would change the properties of SDS and lower or avoid interactions between the denaturant and the protein. These structural data therefore support the hypothesis that MPD avoids disruption of the enzyme structure by SDS and can protect proteins from SDS denaturation.</p

Synthetic fosmidomycin analogues with altered chelating moieties do not inhibit 1-deoxy-D-xylulose 5-phosphate reductoisomerase or Plasmodium falciparum growth in vitro

Fourteen new fosmidomycin analogues with altered metal chelating groups were prepared and evaluated for inhibition of E. coli Dxr, M. tuberculosis Dxr and the growth of P. falciparum K1 in human erythrocytes. None of the synthesized compounds showed activity against either enzyme or the Plasmodia. This study further underlines the importance of the hydroxamate functionality and illustrates that identifying effective alternative bidentate ligands for this target enzyme is challenging

Caractérisation structurale et étude de l'inhibityion de la 1-déoxy-D-xylulose-5-phosphate réductoisomérase (DXR) de E. coli et de la DXR-like (DRL) de B. abortus, par des analogues de la fosmidomycine

The 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway for isoprenoid biosynthesis has come under increased scrutiny as a target for novel antimalarial, antibacterial and antituberculosis agents. 1-Deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) is a key enzyme of the pathway that catalyzes the rearrangement and nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of 1-deoxy-D-xylulose 5-phosphate (DXP) to MEP. The unique properties of DXR make it a remarkable and rational target for drug design. First, it is a vital enzyme for synthesis of isoprenoids in algae, plants, several eubacteria including the pathogenic bacteria like Bacillus anthracis, Helicobacter pylori, Yersinia pestis, Mycobacterium tuberculosis and the malarial parasite, Plasmodium falciparum. Second, there are no functional equivalents to DXR in humans, making it an attractive target for therapeutic intervention. Third, DXR appears to be a valid target and the results from fosmidomycin, the only available DXR inhibitor under clinical trials, suggests synergistic effects with the lincosamide antibiotics, lincomycin and clindamycin. Despite drug design efforts in this area, no successful drug specifically designed to inhibit DXR has emerged yet. Recently, it has been shown that Fosmidomycin inhibited growth of B. abortus cells expressing the Escherichia coli GlpT transporter (required for fosmidomycin uptake), confirming that a DXR-like (DRL) activity exists in these bacteria. The B. abortus DRL protein was found to belong to a family of uncharacterized proteins similar to homoserine dehydrogenase. Our work was focus on the production, purification and characterization of the E. coli DXR enzyme and the B. abortus DRL enzyme. This allowed us to study three series of analogs of fosmidomycin, a specific competitive inhibitor of DXR, available through collaboration with the University of Gent (Prof S.VanCalenberg). Two approaches were used to characterize interaction between inhibitor and enzyme, a theoretical approach by docking and an experimental approach by crystallography.(DOCSC02) -- FUNDP, 201

Crystal structure of type 2 isopentenyl diphosphate isomerase from Thermus thermophilus in complex with inorganic pyrophosphate

The N-terminal region is stabilized in the crystal structure of T. thermophilus type 2 IPP isomerase in complex with inorganic pyrophosphate; providing new insights about the active site and the catalytic mechanism of the enzyme. The PPi moiety is located near the conserved residues, H10, R97, H152, Q157, E158 and W219, and the flavin cofactor. The putative active site of IDI-2 provides interactions for stabilizing a carbocationic intermediate similar to those that stabilize the intermediate in the well-established protonation/deprotonation mechanism of IDI-1

N-Acylated sulfonamide congeners of fosmidomycin lack any inhibitory activity against DXR

The antibiotic fosmidomycin (3a) is an inhibitor of the non-mevalonate pathway for isoprenoid biosynthesis. Four analogues in which an acylated sulfonamide group is substituting for its phosphonate moiety have been synthesized in a fruitless effort to preserve one negative charge in order to increase the accompanying affinity for 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), the fosmidomycin target enzyme.publisher: Elsevier articletitle: N-Acylated sulfonamide congeners of fosmidomycin lack any inhibitory activity against DXR journaltitle: Bioorganic & Medicinal Chemistry Letters articlelink: http://dx.doi.org/10.1016/j.bmcl.2015.02.006 content_type: article copyright: Copyright © 2015 Elsevier Ltd. All rights reserved.status: publishe