How PGL finds a sweet spot in phospholipid membranes: A combined multiscale MD and NMR study.

Glycolipids from pathogenic Mycobacterium tuberculosis play important roles during the interaction of the pathogen with macrophages and can shape the host cell's immune response by modulating its membrane structure and function. Here, we study the phenolic glycolipids (PGLs) present in the envelope of some hypervirulent strains of Mycobacterium tuberculosis and their impact on model membranes. By a combination of molecular modeling and simulations, and solid-state NMR experiments, we show that PGLs, such as the structurally related lipid phthiocerol dimycocerosate, adopt a conical shape in lipid membranes, which destabilizes the lamellar membrane phase and promotes a transition to a nonlamellar inverted-hexagonal phase.

Histidine 73 methylation coordinates β-actin plasticity in response to key environmental factors.

The functional importance of the methylation of histidine 73 (H73) in actin remains unclear. Focusing on cytoplasmic β-actin, present in all mammalian cells, we use molecular dynamics simulations with a polarizable force field and adaptive sampling to examine the effects of H73 methylation. Our results show that methylation enhances nucleotide binding cleft opening, alters allosteric pathways connecting subdomains 2 and 4 (SD2 and SD4) in G-actin, and affects backdoor openings and inorganic phosphate release in F-actin, as validated by biochemical assays.

Dynamic pre-structuration of lipid nanodomain-segregating remorin proteins.

Remorins are multifunctional proteins, regulating immunity, development and symbiosis in plants. When associating to the membrane, remorins sequester specific lipids into functional membrane nanodomains. The multigenic protein family contains six groups, classified upon their protein-domain composition.

Proteasome complexes experience profound structural and functional rearrangements throughout mammalian spermatogenesis.

During spermatogenesis, spermatogonia undergo a series of mitotic and meiotic divisions on their path to spermatozoa. To achieve this, a succession of processes requiring high proteolytic activity are in part orchestrated by the proteasome. The spermatoproteasome (s20S) is specific to the developing gametes, in which the gamete-specific α4s subunit replaces the α4 isoform found in the constitutive proteasome (c20S).

Evidence for amylose inclusion complexes with multiple acyl chain lipids using solid-state NMR and theoretical approaches.

Amylose is known to form inclusion complexes in the presence of hydrophobic guests. Among lipids, only single-chain fatty acids have been reported as possible guests with the surrounding amylose in a well-defined V-helix conformation. Using experimental C solid-state NMR, we studied the formation of inclusion complexes between amylose and a variety of multiple-chains lipids of increasing complexity.

Diversity of the Hydrogen Bond Network and Its Impact on NMR Parameters of Amylose B Polymorph: A Study Using Molecular Dynamics and DFT Calculations Within Periodic Boundary Conditions.

Classical molecular dynamics simulations have been combined with quantum (DFT) calculations of C NMR parameters in order to relate the experimental spectrum of the double-helix form of the amylose B-polymorph in highly crystalline conditions not only to its 3D structure but also to the arrangement of atoms in the crystal lattice. Structures obtained from these simulations or from geometry optimization procedures at the DFT level have shown the presence of hydrogen bond networks between sugars of the same helix or between residues of the two chains of the double helix. C NMR parameter calculations have revealed the impact of such a network on the chemical shifts of carbon atoms.