Search results for "HIV"

A Quantum Mechanic/Molecular Mechanic Study of the Wild-Type and N155S Mutant HIV-1 Integrase Complexed with Diketo Acid

2008

Integrase (IN) is one of the three human immunodeficiency virus type 1 (HIV-1) enzymes essential for effective viral replication. Recently, mutation studies have been reported that have shown that a certain degree of viral resistance to diketo acids (DKAs) appears when some amino acid residues of the IN active site are mutated. Mutations represent a fascinating experimental challenge, and we invite theoretical simulations for the disclosure of still unexplored features of enzyme reactions. The aim of this work is to understand the molecular mechanisms of HIV-1 IN drug resistance, which will be useful for designing anti-HIV inhibitors with unique resistance profiles. In this study, we use mo…

Trimeric HIV Env provides epitope occlusion mediated by hypervariable loops

2014

AbstractHypervariable loops of HIV-1 Env protein gp120 are speculated to play roles in the conformational transition of Env to the receptor binding-induced metastable state. Structural analysis of full-length Env-based immunogens, containing the entire V2 loop, displayed tighter association between gp120 subunits, resulting in a smaller trimeric diameter than constructs lacking V2. A prominent basal quaternary location of V2 and V3′ that challenges previous reports would facilitate gp41-independent gp120-gp120 interactions and suggests a quaternary mechanism of epitope occlusion facilitated by hypervariable loops. Deletion of V2 resulted in dramatic exposure of basal, membrane-proximal gp41…

Nucleotide's bilinear indices: Novel bio-macromolecular descriptors for bioinformatics studies of nucleic acids. I. Prediction of paromomycin's affin…

2009

A new set of nucleotide-based bio-macromolecular descriptors are presented. This novel approach to bio-macromolecular design from a linear algebra point of view is relevant to nucleic acids quantitative structure-activity relationship (QSAR) studies. These bio-macromolecular indices are based on the calculus of bilinear maps on Re(n)[b(mk)(x (m),y (m)):Re(n) x Re(n)--Re] in canonical basis. Nucleic acid's bilinear indices are calculated from kth power of non-stochastic and stochastic nucleotide's graph-theoretic electronic-contact matrices, M(m)(k) and (s)M(m)(k), respectively. That is to say, the kth non-stochastic and stochastic nucleic acid's bilinear indices are calculated using M(m)(k)…

Calculation of binding energy using BLYP/MM for the HIV-1 integrase complexed with the S-1360 and two analogues.

2007

Abstract Integrase (IN) is one of the three human immunodeficiency virus type 1 (HIV-1) enzymes essential for effective viral replication. S-1360 is a potent and selective inhibitor of HIV-1 IN. In this work, we have carried out molecular dynamics (MD) simulations using a hybrid Quantum Mechanics/Molecular Mechanics (QM/MM) approach, to determine the protein–ligand interaction energy for S-1360 and two analogues. Analysis of the MD trajectories reveals that the strongest protein–inhibitor interactions, observed in the three studied complexes, are established with Lys-159 residue and Mg 2+ cation. Calculations of binding energy using BLYP/MM level of theory reveal that there is a direct rela…

Monkeypox virus infection and creatine phosphokinase increase: A case from Italy.

2022

No abstract available.

Grafías para extended voice

2015

Les passages à gué de la Grande Saône, approche archéologique et historique d'un espace fluvial (de Verdun-sur-le-Doubs à Lyon).

2002

National audience

Cambiamento e continuità: i manoscritti del fondo musicale del duomo di Enna

2018

Dal Cinquecento fino agli inizi del Novecento la vita musicale a Enna – cittadina al centro della Sicilia – fu caratterizzata da particolare vivacità. Ciò si dovette soprattutto all'attività della sua più importante istituzione religiosa, la cappella musicale del Duomo, che impiegava un numero stabile di musicisti, per la maggior parte siciliani, ma anche stranieri. Fu soprattutto nel Settecento che molti di loro giunsero a Enna da Napoli, il più prestigioso centro musicale dell'epoca. Vi troviamo virtuosi cantori e strumentisti, ma anche compositori come Luigi Platone o Giuseppe Coppola, entrambi giunti in Sicilia alla fine del secolo e divenuti maestri dell'istituzione. La prolifica attiv…

The cost of replication fidelity in human immunodeficiency virus type 1.

2006

Mutation rates should be governed by at least three evolutionary factors: the need for beneficial mutations, the benefit of minimizing the mutational load and the cost of replication fidelity. RNA viruses show high mutation rates compared with DNA micro-organisms, and recent findings suggest that the cost of fidelity might play a role in the evolution of increased mutation rates. Here, by analysing previously published data from HIV-1 reverse transcriptase in vitro assays, we show a trade-off between enzymatic accuracy and the maximum rate of polymerization, thus providing a biochemical basis for the fitness cost of fidelity in HIV-1. This trade-off seems to be related to inefficient exten…

The external domains of the HIV-1 envelope are a mutational cold spot

2015

In RNA viruses, mutations occur fast and have large fitness effects. While this affords remarkable adaptability, it can also endanger viral survival due to the accumulation of deleterious mutations. How RNA viruses reconcile these two opposed facets of mutation is still unknown. Here we show that, in human immunodeficiency virus (HIV-1), spontaneous mutations are not randomly located along the viral genome. We find that the viral mutation rate experiences a threefold reduction in the region encoding the most external domains of the viral envelope, which are strongly targeted by neutralizing antibodies. This contrasts with the hypermutation mechanisms deployed by other, more slowly mutating …