Fig. 4: MreB mutants alter twist angles in simulation.
From: Chiral twisting in a bacterial cytoskeletal polymer affects filament size and orientation
a Mutations in MreB investigated via MD simulations mapped onto the CcMreB crystal structure. These mutations were previously identified to alter cell shape14,19, and are conserved between CcMreB (residue numbers in blue) and EcMreB (residue numbers in light gray). Colored spheres: mutated residues. Orange: ATP molecule. Gray: MreB protein structure. b Distributions of twist angles in simulations of CcMreB mutants. All systems started with zero twisting. E275D and R121C twisted less than wild-type MreB, while V53A and I138V twisted more. Dots are histograms from the last 40 ns of each simulation, and curves are Gaussian fits of the histograms. Inset: MD simulations for mutants in an EcMreB homology model also exhibited left-handed twisting, and the twist angles were correlated with those of the corresponding CcMreB mutants. Data points are mean ± S.D. from Gaussian fits. c Distributions of twist angles with and without RodZ binding. For wildtype and the V53A mutant, binding of the cytoplasmic tail of RodZ decreased twisting. The effect of RodZ binding was approximately additive to the effects of MreB mutation, such that the V53A-RodZ system twisted more than the WT-RodZ system. Dots are histograms from the last 40 ns of each simulation, and curves are Gaussian fits of the histograms.
