16 research outputs found
Biophysical Characterization and Membrane Interaction of the Two Fusion Loops of Glycoprotein B from Herpes Simplex Type I Virus
The molecular mechanism of entry of herpesviruses requires a multicomponent fusion system. Cell invasion by Herpes simplex virus (HSV) requires four virally encoded glycoproteins: namely gD, gB and gH/gL. The role of gB has remained elusive until recently when the crystal structure of HSV-1 gB became available and the fusion potential of gB was clearly demonstrated. Although much information on gB structure/function relationship has been gathered in recent years, the elucidation of the nature of the fine interactions between gB fusion loops and the membrane bilayer may help to understand the precise molecular mechanism behind herpesvirus-host cell membrane fusion. Here, we report the first biophysical study on the two fusion peptides of gB, with a particular focus on the effects determined by both peptides on lipid bilayers of various compositions. The two fusion loops constitute a structural subdomain wherein key hydrophobic amino acids form a ridge that is supported on both sides by charged residues. When used together the two fusion loops have the ability to significantly destabilize the target membrane bilayer, notwithstanding their low bilayer penetration when used separately. These data support the model of gB fusion loops insertion into cholesterol enriched membranes
Characterization of a new class of blue-fluorescent lipid droplet markers for live-cell imaging in plants
Impaired cisplatin influx in an A2780 mutant cell line - Evidence for a putative, cis-configuration-specific, platinum influx transporter
Impaired cisplatin influx in an A2780 mutant cell line - Evidence for a putative, cis-configuration-specific, platinum influx transporter
Rapeseed oil‑rich diet alters hepatic mitochondrial membrane lipid composition and disrupts bioenergetics
Diet is directly related with physiological alterations
occurring at a cell and subcellular level. However,
the role of diet manipulation on mitochondrial physiology
is still largely unexplored. Aiming at correlating diet with
alterations of mitochondrial membrane composition and
bioenergetics, Wistar-Han male rats were fed for 11, 22 and
33 days with a rapeseed oil-based diet and mitochondrial
bioenergetics, and membrane composition were compared
at each time point with a standard diet group. Considerable
differences were noticed in mitochondrial membrane lipid composition, namely in terms of fatty acyl chains and relative
proportions of phospholipid classes, the modified diet
inducing a decrease in the saturated to unsaturated molar
ratio and an increase in the phosphatidylcholine to phosphatidylethanolamine
molar ratio. Mass spectrometry lipid
analysis showed significant differences in the major species
of cardiolipin, with an apparent increased incorporation
of oleic acid as a result of exposure to the modified
diet. Rats fed the modified diet during 22 days showed
decreased hepatic mitochondrial state 3 respiration and
were more susceptible to Ca2+-induced transition pore
opening. Rapeseed oil-enriched diet also appeared to promote
a decrease in hydroperoxide production by the respiratory
chain, although a simultaneous decrease in vitamin E
content was detected. In conclusion, our data indicate that
the rapeseed oil diet causes negative alterations on hepatic
mitochondrial bioenergetics, which may result from membrane
remodeling. Such alterations may have an impact not
only on energy supply to the cell, but also on drug-induced
hepatic mitochondrial liabilities.The project was supported by the Foundation
for Science and Technology with FEDER/COMPETE/National
Budget funds (research grants PTDC/QUI–QUI/101409/2008 to P. J.
O., PTDC/QUI-BIQ/103001/2008 to A. S. J. and strategic grant PEst-
C/SAU/LA0001/2011to the CNC). J. P. M. and A. M. S. acknowledge
FCT for Ph.D. grants SFRH/BD/37626/2007 and PTDC/AGRALI/
108326/2008, respectively