Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Comparison of the malaria parasite and mammalian protein prenyltransferases and their cellular substrates is important for establishing this enzyme as a target for developing antimalarial agents. Nineteen heptapeptides differing only in their carboxyl-terminal amino acid were tested as alternative substrates of partially purified Plasmodium falciparum protein farnesyltransferase. Only NRSCAIM and NRSCAIQ serve as substrates, with NRSCAIM being the best. Peptidomimetics, FTI-276 and GGTI-287, inhibit the transferase with IC(50) values of 1 and 32 nm, respectively. Incubation of P. falciparum-infected erythrocytes with [(3)H]farnesol labels 50- and 22-28-kDa proteins, whereas [(3)H]geranylgeraniol labels only 22-28-kDa proteins. The 50-kDa protein is shown to be farnesylated, whereas the 22-28-kDa proteins are geranylgeranylated, irrespective of the labeling prenol. Protein labeling is inhibited more than 50% by either 5 microm FTI-277 or GGTI-298. The same concentration of inhibitors also inhibits parasite growth from the ring stage by 50%, decreases expression of prenylated proteins as measured with prenyl-specific antibody, and inhibits parasite differentiation beyond the trophozoite stage. Furthermore, differentiation specific prenylation of P. falciparum proteins is demonstrated. Protein labeling is detected predominantly during the trophozoite to schizont and schizont to ring transitions. These results demonstrate unique properties of protein prenylation in P. falciparum: a limited specificity of the farnesyltransferase for peptide substrates compared with mammalian enzymes, the ability to use farnesol to label both farnesyl and geranylgeranyl moieties on proteins, differentiation specific protein prenylation, and the ability of peptidomimetic prenyltransferase inhibitors to block parasite differentiation.
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PMID:Protein farnesyltransferase and protein prenylation in Plasmodium falciparum. 1219 69

Farnesyltransferase (FTase) and geranylgeranyltransferase type-I (GGTase-I) are two members of protein prenyltransferases, which play critical roles in lipid post-translational modifications. Potent inhibitors of FTase and GGTase-I have been confirmed to show favorable influence on the therapies of various diseases, such as cancers, malaria and Toxoplasmosis. However, designing highly specific inhibitors toward FTase or GGTase-I without influencing their binding affinity remains a big challenge. In this work, molecular docking, molecular dynamics (MD) simulations and MM/GBSA free energy calculations were employed to study the bindings of two highly selective inhibitors (lonafarnib and GGTI-2133) towards FTase or GGTase-I. The specificities of the studied inhibitors derived from the predicted binding free energies are consistent with the experimental data. The analysis of the energetic components illustrates that both the non-polar and polar interactions play critical roles in determining the specificity between FTase and GGTase-I. Moreover, the protein-inhibitor interaction spectra for the studied inhibitors were determined through the decomposition of the binding free energies, and the important residues for binding and specificity were highlighted. Our study provides useful information for the rational design of selective FTase or GGTase-I inhibitors.
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PMID:Theoretical studies on binding and specificity mechanisms of farnesyltransferase (FTase) and geranylgeranyltransferase type-I (GGTase-I) inhibitors by molecular modeling. 2444 14