Filament structure and subcellular organization of the bacterial intermediate filament-like protein crescentin.

The protein crescentin is required for the crescent shape of the freshwater bacterium (). Crescentin forms a filamentous structure on the inner, concave side of the curved cells. It shares features with eukaryotic intermediate filament (IF) proteins, including the formation of static filaments based on long and parallel coiled coils, the protein's length, structural roles in cell and organelle shape determination and the presence of a coiled coil discontinuity called the "stutter.

Efficient Empirical Valence Bond Simulations with GROMACS.

We describe a protocol to perform empirical valence bond (EVB) simulations using GROMACS software. EVB is a fast and reliable method that allows one to determine the reaction free-energy profiles in complex systems, such as enzymes, by employing classical force fields to represent a chemical reaction. Therefore, running EVB simulations is basically as fast as any classical molecular dynamics simulation, and the method uses standard free-energy calculations to map the free-energy change along a given reaction path.

Computational design of the temperature optimum of an enzyme reaction.

Cold-adapted enzymes are characterized both by a higher catalytic activity at low temperatures and by having their temperature optimum down-shifted, compared to mesophilic orthologs. In several cases, the optimum does not coincide with the onset of protein melting but reflects some other type of inactivation. In the psychrophilic α-amylase from an Antarctic bacterium, the inactivation is thought to originate from a specific enzyme-substrate interaction that breaks around room temperature.

Cryo-EM structure of the bacterial divisome core complex and antibiotic target FtsWIQBL.

In most bacteria, cell division relies on the synthesis of new cell wall material by the multiprotein divisome complex. Thus, at the core of the divisome are the transglycosylase FtsW, which synthesises peptidoglycan strands from its substrate Lipid II, and the transpeptidase FtsI that cross-links these strands to form a mesh, shaping and protecting the bacterial cell. The FtsQ-FtsB-FtsL trimeric complex interacts with the FtsWI complex and is involved in regulating its enzymatic activities; however, the structure of this pentameric complex is unknown.

Calculation of Heat Capacity Changes in Enzyme Catalysis and Ligand Binding.

It has been suggested that heat capacity changes in enzyme catalysis may be the underlying reason for temperature optima that are not related to unfolding of the enzyme. If this were to be a common phenomenon, it would have major implications for our interpretation of enzyme kinetics. In most cases, the support for the possible existence of a nonzero (negative) activation heat capacity, however, only relies on fitting such a kinetic model to experimental data.