Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A sulfate (GE-3-S) prepared by chlorosulfonic acid treatment of GE-3, a partially acetylated beta(1----6) glucan of the lichen Umbilicaria esculenta, inhibited the cytopathic effect of human immunodeficiency virus (HIV) and suppressed the HIV-antigen expression in Molt-4 (clone 8) cells. GE-3-S also suppressed the giant cell formation of HIV-infected Molt-4 cells, and inhibited HIV-induced plaque formation by 50% at the dose of 19.5 micrograms/ml and completely at 250 micrograms/ml in MT4 cells. GE-3-S had no direct effect on the reverse transcriptase of HIV.
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PMID:Inhibitory effect of a lichen polysaccharide sulfate, GE-3-S, on the replication of human immunodeficiency virus (HIV) in vitro. 257 16

Swertifrancheside [1], a new flavonone-xanthone glucoside isolated from Swertia franchetiana, 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2], a triterpene isolated from the roots of Maprounea africana, and protolichesterinic acid [3], an aliphatic alpha-methylene-gamma-lactone isolated from the lichen Cetraria islandica, were found to be potent inhibitors of the DNA polymerase activity of human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT), with 50% inhibitory doses (IC50 values) of 43, 3.7, and 24 microM, respectively. They were not cytotoxic with cultured mammalian cells. The kinetic mechanisms by which compounds 1-3 inhibited HIV-1 RT were studied as was their potential to inhibit other nucleic acid polymerases. Swertifrancheside [1] bound to DNA and was shown to be a competitive inhibitor with respect to template-primer, but a mixed-type competitive inhibitor with respect to TTP. On the other hand, 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2] and protolichesterinic acid [3] were mixed-type competitive inhibitors with respect to template-primer and noncompetitive inhibitors with respect to TTP. Therefore, the mechanism of action of 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2] and protolichesterinic acid [3] as HIV-1 RT inhibitors involves nonspecific binding to the enzyme at nonsubstrate binding sites, whereas swertifrancheside [1] inhibits enzyme activity by binding to the template-primer.
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PMID:Mechanistic evaluation of new plant-derived compounds that inhibit HIV-1 reverse transcriptase. 756 95

To identify the biosynthetic gene cluster responsible for the biosynthesis of the polyketide usnic acid we carried out the de novo genome sequencing of the fungal partner of Cladonia uncialis. This was followed by comprehensive in silico annotation of polyketide synthase (PKS) genes. The biosynthesis of usnic acid requires a non-reducing PKS possessing a carbon methylation (CMeT) domain, a terminal Claisen cyclase (CLC) domain, and an accompanying oxidative enzyme that dimerizes methylphloracetophenone to usnic acid. Of the 32 candidate PKS genes identified in the mycobiont genome, only one was identified as consistent with these biosynthetic requirements. This gene cluster contains two genes encoding a non-reducing PKS and a cytochrome p450, which have been respectively named methylphloracetophenone synthase (MPAS) and methylphloracetophenone oxidase (MPAO). Both mpas and mpao were demonstrated to be transcriptionally active by reverse transcriptase-PCR of the mRNA in a lichen sample that was observed by HPLC to produce usnic acid. Phylogenetic analysis of the bioinformatically identified ketosynthase (KS) and CLC domains of MPAS demonstrated that mpas grouped within a unique clade and that mpas could be used as a phylogenetic probe to identify other MPAS genes.
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PMID:Putative identification of the usnic acid biosynthetic gene cluster by de novo whole-genome sequencing of a lichen-forming fungus. 2689 59