HIV-1 Gag MA domain binds to cardiolipin in a binding mode distinct from virus assemble mediator PI(4,5)P.

The human immunodeficiency virus type 1 (HIV-1) Gag protein is responsible for facilitating HIV-1 virion assembly and budding. Our study demonstrates that cardiolipin (CL), a component found in the inner mitochondrial membrane, exhibits the highest binding affinity to the N-terminal MA domain of the HIV-1 Gag protein within the lipid group of host cells. To assess this binding interaction, we synthesized short acyl chain derivatives of CL and employed surface plasmon resonance (SPR) analysis to determine the dissociation constants (Kd) for CL and the MA domain.

Significance of Circulating Remnant Lipoprotein Cholesterol Levels Measured by Homogeneous Assay in Patients with Type 2 Diabetes.

Remnant lipoproteins (RLs), which are typically present at high concentrations in patients with type 2 diabetes mellitus (T2DM), are associated with cardiovascular disease (CVD). Although an RL cholesterol homogeneous assay (RemL-C) is available for the measurement of RL concentrations, there have been no studies of the relationship between RemL-C and clinical parameters in T2DM. Therefore, we evaluated the relationships between RemL-C and CVD-related parameters in patients with T2DM.

Development of chimeric receptor activator of nuclear factor-kappa B with glutathione S-transferase in the extracellular domain: Artificial switch in a membrane receptor.

Various chimeric receptors have been developed and used for biological experiments. In the present study, we constructed three types of chimeric receptor activator of nuclear factor-kappa B (RANK) with the glutathione S-transferase (GST) protein in the extracellular domain, and stimulated them using newly synthesized chemical trimerizers with three glutathiones. Although this stimulation did not activate these proteins, we unexpectedly found that the chimera named RANK-GST-SC, in which GST replaced a major part of the RANK extracellular domain, activated nuclear factor-kappa B (NF-κB) signaling approximately sixfold more strongly than wild-type RANK without the ligand.

A homogeneous assay to determine high-density lipoprotein subclass cholesterol in serum.

Existing methods to measure high-density lipoprotein cholesterol (HDL-C) subclasses (HDL-C and HDL-C) are complex and require proficiency, and thus there is a need for a convenient, homogeneous assay to determine HDL-C subclasses in serum. Here, cholesterol reactivities in lipoprotein fractions [HDL, HDL, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL)] toward polyethylene glycol (PEG)-modified enzymes were determined in the presence of varying concentrations of dextran sulfate and magnesium nitrate. Particle sizes formed in the lipoprotein fractions were measured by dynamic light scattering.

A clue to unprecedented strategy to HIV eradication: "Lock-in and apoptosis".

Despite the development of antiretroviral therapy against HIV, eradication of the virus from the body, as a means to a cure, remains in progress. A "kick and kill" strategy proposes "kick" of the latent HIV to an active HIV to eventually be "killed". Latency-reverting agents that can perform the "kick" function are under development and have shown promise.

A bioconjugate leveraging xenoreactive antibodies to alleviate cocaine-induced behavior.

A method for potentiating the response to an anti-cocaine vaccine by leveraging xenoreactive antibodies against the carbohydrate epitope Galα1,3-Gal (GAL) was found to result in a highly specific anti-cocaine response that was able to significantly attenuate cocaine-induced locomotion at 20 mg kg with superior efficacy compared to a standard conjugate.

The design and synthesis of an α-Gal trisaccharide epitope that provides a highly specific anti-Gal immune response.

Carbohydrate antigens displaying Galα(1,3)Gal epitopes are recognized by naturally occurring antibodies in humans. These anti-Gal antibodies comprise up to 1% of serum IgG and have been viewed as detrimental as they are responsible for hyperacute organ rejections. In order to model this condition, α(1,3)galactosyltransferase-knockout mice are inoculated against the Galα(1,3)Gal epitope.

Differences in reaction specificity toward lipoprotein X and abnormal LDL among 6 homogeneous assays for LDL-cholesterol.

Background: We investigated the reaction specificity toward cholesterol in lipoprotein X (Lp-X) and abnormal LDL among 6 homogeneous assays for low-density lipoprotein cholesterol (LDL-C) based on different measurement principles.

Methods: The homogeneous LDL-C assays used were based on the liquid selective detergent, selective solubilization, elimination, enzyme-selective protection, calixarene complex, and phosphate complex inhibition methods. The fraction with a density of 1.

Design and synthesis of lipid-coupled inositol 1,2,3,4,5,6-hexakisphosphate derivatives exhibiting high-affinity binding for the HIV-1 MA domain.

The precursor of Gag protein (Pr55(Gag)) of human immunodeficiency virus, the principal structural component required for virus assembly, is known to bind d-myo-phosphatidylinositol 4,5-bisphosphate (PIP2). The N-terminus of Pr55(Gag), the MA domain, plays a critical role in the binding of Pr55(Gag) to the plasma membrane. Herein, we designed and synthesized myo-phosphatidylinositol 2,3,4,5,6-pentakisphosphate (PIP5) derivatives comprising highly phosphorylated inositol and variously modified diacylglycerol to examine the MA-binding properties.

Removal of toxin (tetrodotoxin) from puffer ovary by traditional fermentation.

The amounts of puffer toxin (tetrodotoxin, TTX) extracted from the fresh and the traditional Japanese salted and fermented "Nukazuke" and "Kasuzuke" ovaries of Takifugu stictonotus (T. stictonotus) were quantitatively analyzed in the voltage-dependent sodium current (I(Na)) recorded from mechanically dissociated single rat hippocampal CA1 neurons. The amount of TTX contained in "Nukazuke" and "Kasuzuke" ovaries decreased to 1/50-1/90 times of that of fresh ovary during a salted and successive fermented period over a few years.

Design and synthesis of biotinylated inositol 1,3,4,5-tetrakisphosphate targeting Grp1 pleckstrin homology domain.

A bifunctional molecule containing biotin and d-myo-inositol 1,3,4,5-tetrakisphosphate was synthesized. This molecule was designed on the basis of X-ray structure of the complex of d-myo-inositol 1,3,4,5-tetrakisphosphates, Ins(1,3,4,5)P(4), and Grp1 PH (general receptor of phosphoinositides pleckstrin homology) domain for the application to the widely employed biotin-avidin techniques. The building block of inositol moiety was synthesized starting with myo-inositol and assembled with the biotin-linker moiety through a phosphate linkage.

Highly sensitive analysis of the interaction between HIV-1 Gag and phosphoinositide derivatives based on surface plasmon resonance.

Human immunodeficiency virus type 1 (HIV-1) Gag protein is the principal structural component of the HIV particle. Localization of the Pr55(Gag) protein to the plasma membrane initiates virus assembly. Recent studies indicated that d-myo-phosphatidylinositol (PI) 4,5-bisphosphate (PI(4,5)P2) regulates Pr55(Gag) localization and assembly.

Design and synthesis of biotinylated inositol phosphates relevant to the biotin-avidin techniques.

Six bifunctional molecules containing biotin and various inositol phosphates were synthesized. These compounds were designed on the basis of X-ray structures of the complexes of D-myo-inositol 1,4,5-triphosphates (IP(3)) and phospholipase C delta pleckstrin homology domain (PLCdelta PH) considering the application to the biotin-avidin techniques. The building blocks of the inositol moiety were synthesized starting with optically resolved myo-inositol derivatives and assembled to the biotin linker through a phosphate linkage.

Quantitative analysis of toxin extracts from various tissues of wild and cultured puffer fish by an electrophysiological method.

We observed the effects of the toxin extracted from various tissues of wild and cultured puffer fish on voltage-dependent sodium current (I(Na)) using single rat CA1 neurons, and compared the results with that of tetrodotoxin (TTX). Toxin extracts from wild puffer fish inhibited I(Na) in a dilution-dependent manner, and toxin extracts from liver or ovary produced 300 times greater inhibition than that from muscle, and corresponded to about 65 microg TTX/g tissue. We also used puffer fish cultured in net cages or in tanks set up on land, in an attempt to isolate them from the food chain.