Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:APRD00631 (Gel)
 14,881 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Capsid protein (p24;CA) of human immunodeficiency virus type 1 (HIV-1) was synthesized in Escherichia coli strain BL21 (DE3) using a plasmid encoding a truncated HIV-1 gag/pol gene. The plasmid, which contained a mutation in the frameshift region, expressed viral proteinase (PR), a pol gene product, in the gag reading frame, resulting in efficient processing of mature CA and other gag-related products. The expressed CA is soluble, recognized by monoclonal antibodies directed against HIV CA and has an N-terminal sequence identical to that of CA purified from HIV. Purification was done under mild conditions where coexpressed HIV PR retained enzymatic activity. Milligram quantities of 90% pure CA protein were obtained after chromatography on DEAE cellulose followed by facilitated aggregation of the CA in the unbound fraction. The precipitated CA was readily dissolved in low ionic strength aqueous buffer. Gel exclusion chromatography results indicated that, in solution, CA existed in oligomeric form.
 ...
PMID:Expression in Escherichia coli and purification of human immunodeficiency virus type 1 capsid protein (p24). 212 31

Recombinant Rev protein of human immunodeficiency virus type 1 has been expressed in Escherichia coli and purified by ion-exchange and gel-filtration chromatography. Specific binding of the purified protein to the Rev-responsive element of the viral RNA is demonstrated. Physical characterization of the purified protein by circular dichroism and intrinsic fluorescence spectroscopy indicate that the protein preparation is suitable for structural analysis. Circular dichroism measurements show that the protein is approximately 40-45% alpha-helix. Tryptophan fluorescence measurements suggest that the single tryptophan residue is located near the surface of the protein. Gel-filtration chromatography of the protein indicates that it has an apparent molecular mass of 33,000 daltons. This suggests that the protein in solution forms a stable tetramer consisting of monomers having molecular mass of 13,000 daltons.
 ...
PMID:Purification and characterization of recombinant Rev protein of human immunodeficiency virus type 1. 221 89

A solid phase assay for human immunodeficiency virus (HIV) protease using an immobilized substrate, Affi Gel 10-Gly-Gly-Gly-Gly-Val-Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln-[3H]Gly-OH has been devised. The Tyr-Pro bond of the substrate was hydrolyzed by the protease, releasing the radiolabeled cleavage product, Pro-Ile-Val-Gln-[3H]Gly-OH, into the supernatant. The pH optimum was found to be 6.0, and a high ionic strength was required for maximal activity. The solid phase assay is usable for convenient monitoring of purification procedures, and rapid screening of inhibitors of HIV protease.
 ...
PMID:A solid phase assay for the protease of human immunodeficiency virus. 222 72

The N-linked oligosaccharide structures on the envelope glycoprotein gp120 of human immunodeficiency virus 1 derived from chronically infected lymphoblastoid (H9) cells have been investigated by enzymatic microsequencing after release from protein by hydrazinolysis, labeling with NaB3H4, and chromatography on adsorbent columns of Phaseolus vulgaris erythrophytohemagglutinin and Ricinus communis agglutinin (Mr 120,000) and on Bio-Gel P-4. A substantially greater diversity of oligosaccharide structures was detected than among those released by hydrazinolysis from recombinant gp120 produced in Chinese hamster ovary cells and investigated by similar procedures (Mizuochi, T., Spellman, M.W., Larkin, M., Solomon, J., Basa, L.J., and Feizi, T. (1988) Biochem J. 254, 599-603) and among those released by endoglycosidases from virus-derived gp120 isolated from infected H9 cells after metabolic labeling with D-[2-3H]mannose or D-[6-3H]glucosamine (Geyer, H., Holschbach, L., Hunsmann, G., and Schneider, J. (1988) J. Biol. Chem. 263, 11760-11767). In this study, 16% of the oligosaccharides were identified as complex-type bi-, tri-, and tetraantennary sialo-oligosaccharides with bisecting N-acetylglucosamine residues. Such structures were lacking on recombinant gp120 and could not be detected on the metabolically labeled, virus-derived glycoprotein. As in the earlier investigations, complex-type chains lacking bisecting N-acetylglucosamine residues, hybrid-type chains, and a series of high mannose-type structures with 5-9 mannose residues were identified. In addition, an array of complex-type chains having one or more outer chains with beta-galactosyl residues were detected in this study, but with additional substitutions that require further investigation. The number of potential N-glycosylation sites on gp120 is on the order of 20, but the oligosaccharide structures are far more numerous. Thus, the salient conclusion from this and earlier investigations is that alternative structures occur on at least some of the glycosylation sites and that numerous glycosylation variants of this glycoprotein are produced even within a single cell line. Since the glycosylation is the product of host cell glycosyltransferases, an even greater number of glycosylation variants of gp120 are predicted to arise from the heterogeneous cell populations harboring the virus in in vivo infection.
 ...
PMID:Diversity of oligosaccharide structures on the envelope glycoprotein gp 120 of human immunodeficiency virus 1 from the lymphoblastoid cell line H9. Presence of complex-type oligosaccharides with bisecting N-acetylglucosamine residues. 234 93

Expression of human immunodeficiency virus type 1 structural proteins requires both the viral Rev trans-activator and its cis-acting RNA target sequence, the Rev response element (RRE). The RRE has been mapped to a conserved region of the HIV-1 env gene and is predicted to form a complex, highly stable RNA stem-loop structure. Site-directed mutagenesis was used to define a small subdomain of the RRE, termed stem-loop II, that is essential for biological activity. Gel retardation assays demonstrated that the Rev trans-activator is a sequence-specific RNA binding protein. The RRE stem-loop II subdomain was found to be both necessary and sufficient for the binding of Rev by the RRE. We propose that the HIV-1 Rev trans-activator belongs to a new class of sequence-specific RNA binding proteins characterized by the presence of an arginine-rich binding motif.
 ...
PMID:HIV-1 structural gene expression requires binding of the Rev trans-activator to its RNA target sequence. 240 30

Eleven povidone-iodine-containing products (Betadine) and chlorhexidine gluconate solution were tested for their ability to inactivate human immunodeficiency virus (HIV) in a cell culture system. All Betadine products completely inactivated the virus at povidone-iodine concentrations of greater than or equal to 0.5% (10- to 20-fold dilutions of stock) except for Betadine Lubricating Antiseptic Gel, which required 2.5% for efficacy (1:2 dilution). Chlorhexidine gluconate completely inactivated HIV at concentrations of greater than or equal to 0.2% (1:100 dilution of laboratory stock; 1:20 dilution of commercial stock). Betadine douche and medicated douche did not inactivate HIV at the concentrations recommended for clinical use (0.33% and 0.25%, respectively) but were effective at povidone-iodine concentrations of 0.5%. Inactivation appeared to be immediate since no difference in efficacy based on length of exposure to the microbicide was detected. Thus, both microbicides are highly effective at killing HIV in vitro.
 ...
PMID:Inactivation of human immunodeficiency virus by Betadine products and chlorhexidine. 246 3

The enhancer-binding factor of human immunodeficiency virus (HIV)-1 was purified from human B cells by sequence-specific duplex oligonucleotide affinity chromatography. Gel retardation assay and footprint analysis showed that the purified factor bound specifically to the HIV-1 enhancer sequence, and protected both direct repeats in the HIV-1 enhancer. The purified factor consisted of four main polypeptides of the molecular weight of 36,000-42,000. At least three of them had enhancer-binding activity after elution from sodium dodecyl sulfate-polyacrylamide gel and renaturation. UV cross-linking analysis also showed that at least two of the polypeptides in purified fraction had a binding activity specific for the HIV-1 enhancer. The purified factor activated transcription from the HIV-1 promoter in vitro, confirming that it was indeed a transcription factor for HIV-1. The purified factor also recognized sequences in the immunoglobulin kappa gene enhancer and the major histocompatibility complex class I gene enhancer with almost the same affinity as the HIV-1 enhancer. These results suggested the existence of multiple proteins which recognize the kappa B-related sequences. This regulatory factor should help in the study of the biochemical pathway underlying HIV production from latently infected cells.
 ...
PMID:Identification and purification of the enhancer-binding factor of human immunodeficiency virus-1. Multiple proteins and binding to other enhancers. 253 25

The transactivator protein, tat, encoded by the human immunodeficiency virus is a key regulator of viral transcription. Activation by the tat protein requires sequences downstream of the transcription initiation site called the transactivating region (TAR). RNA derived from the TAR is capable of forming a stable stem-loop structure and the maintenance of both the stem structure and the loop sequences located between +19 and +44 is required for complete in vivo activation by tat. Gel retardation assays with RNA from both wild-type and mutant TAR constructs generated in vitro with SP6 polymerase indicated specific binding of HeLa nuclear proteins to the TAR. To characterize this RNA-protein interaction, a method of chemical "imprinting" has been developed using photoactivated uranyl acetate as the nucleolytic agent. This reagent nicks RNA under physiological conditions at all four nucleotides in a reaction that is independent of sequence and secondary structure. Specific interaction of cellular proteins with TAR RNA could be detected by enhanced cleavages or imprints surrounding the loop region. Mutations that either disrupted stem base-pairing or extensively changed the primary sequence resulted in alterations in the cleavage pattern of the TAR RNA. Structural features of the TAR RNA stem-loop essential for tat activation are also required for specific binding of the HeLa cell nuclear protein.
 ...
PMID:Specific binding of a HeLa cell nuclear protein to RNA sequences in the human immunodeficiency virus transactivating region. 254 77

Expression of human immunodeficiency virus type 1 (HIV-1) can be activated in a chronically infected T-cell line (ACH2 cells) by a cytokine, human tumor necrosis factor alpha (TNF-alpha). TNF-alpha treatment of ACH2 cells resulted in an increase in steady-state levels of HIV RNA and HIV transcription. Gel mobility shift assays demonstrated that the transcriptional activation of the HIV long terminal repeat (LTR) by TNF-alpha was associated with the induction of a nuclear factor(s) binding to the NF-kappa B sites in the LTR. Deletion of the NF-kappa B sites from the LTR eliminated activation by TNF-alpha in T cells transfected with plasmids in which the HIV LTR directed the expression of the bacterial chloramphenicol acetyltransferase gene. Thus, TNF-alpha appears to activate HIV RNA and virus production by ACH2 cells through the induction of transcription-activating factors that bind to the NF-kappa B sequences in the HIV LTR.
 ...
PMID:Tumor necrosis factor alpha activates human immunodeficiency virus type 1 through induction of nuclear factor binding to the NF-kappa B sites in the long terminal repeat. 276 7

It has been previously shown that herpes simplex virus type 1 (HSV-1) infection of HeLa cells results in augmentation of gene expression directed by the human immunodeficiency virus (HIV) long terminal repeat (LTR). This effect is presumably mediated by protein interactions with the LTR. We have used two different assays of DNA-protein interactions to study the HSV-induced activation of the HIV LTR. Activation of the HIV LTR is associated with increased protein binding to LTR sequences in a region including the NF-kappa B/core enhancer and the Sp1 binding sequences as monitored by an exonuclease protection assay. Gel retardation assays demonstrated that HSV-1 infection resulted in the induction of a nuclear factor(s) that binds to the NF-kappa B/core enhancer sequence. In addition to the activation of the HIV LTR, HSV induction of NF-kappa B activity may be important for the regulation of HSV gene expression during a herpesvirus infection.
 ...
PMID:Activation of the human immunodeficiency virus long terminal repeat by herpes simplex virus type 1 is associated with induction of a nuclear factor that binds to the NF-kappa B/core enhancer sequence. 284 25


<< Previous 1 2 3 4 5 6 7 8 Next >>