De novo determination of mosquitocidal Cry11Aa and Cry11Ba structures from naturally-occurring nanocrystals.

Cry11Aa and Cry11Ba are the two most potent toxins produced by mosquitocidal Bacillus thuringiensis subsp. israelensis and jegathesan, respectively. The toxins naturally crystallize within the host; however, the crystals are too small for structure determination at synchrotron sources.

Nucleation of protein mesocrystals via oriented attachment.

Self-assembly of proteins holds great promise for the bottom-up design and production of synthetic biomaterials. In conventional approaches, designer proteins are pre-programmed with specific recognition sites that drive the association process towards a desired organized state. Although proven effective, this approach poses restrictions on the complexity and material properties of the end-state.

MAP6 is an intraluminal protein that induces neuronal microtubules to coil.

Neuronal activities depend heavily on microtubules, which shape neuronal processes and transport myriad molecules within them. Although constantly remodeled through growth and shrinkage events, neuronal microtubules must be sufficiently stable to maintain nervous system wiring. This stability is somehow maintained by various microtubule-associated proteins (MAPs), but little is known about how these proteins work.

Serial femtosecond crystallography on in vivo-grown crystals drives elucidation of mosquitocidal Cyt1Aa bioactivation cascade.

Cyt1Aa is the one of four crystalline protoxins produced by mosquitocidal bacterium Bacillus thuringiensis israelensis (Bti) that has been shown to delay the evolution of insect resistance in the field. Limiting our understanding of Bti efficacy and the path to improved toxicity and spectrum has been ignorance of how Cyt1Aa crystallizes in vivo and of its mechanism of toxicity. Here, we use serial femtosecond crystallography to determine the Cyt1Aa protoxin structure from sub-micron-sized crystals produced in Bti.

Measuring Particle Size Distribution by Asymmetric Flow Field Flow Fractionation: A Powerful Method for the Preclinical Characterization of Lipid-Based Nanoparticles.

Particle size distribution and stability are key attributes for the evaluation of the safety and efficacy profile of medical nanoparticles (Med-NPs). Measuring particle average size and particle size distribution is a challenging task which requires the combination of orthogonal high-resolution sizing techniques, especially in complex biological media. Unfortunately, despite its limitations, due to its accessibility, low cost, and easy handling, batch mode dynamic light scattering (DLS) is still very often used as the only approach to measure particle size distribution in the nanomedicine field.

Bacteriophage T5 tail tube structure suggests a trigger mechanism for Siphoviridae DNA ejection.

The vast majority of phages, bacterial viruses, possess a tail ensuring host recognition, cell wall perforation and safe viral DNA transfer from the capsid to the host cytoplasm. Long flexible tails are formed from the tail tube protein (TTP) polymerised as hexameric rings around and stacked along the tape measure protein (TMP). Here, we report the crystal structure of T5 TTP pb6 at 2.

Structural insights into the Escherichia coli lysine decarboxylases and molecular determinants of interaction with the AAA+ ATPase RavA.

The inducible lysine decarboxylase LdcI is an important enterobacterial acid stress response enzyme whereas LdcC is its close paralogue thought to play mainly a metabolic role. A unique macromolecular cage formed by two decamers of the Escherichia coli LdcI and five hexamers of the AAA+ ATPase RavA was shown to counteract acid stress under starvation. Previously, we proposed a pseudoatomic model of the LdcI-RavA cage based on its cryo-electron microscopy map and crystal structures of an inactive LdcI decamer and a RavA monomer.

Assembly principles of a unique cage formed by hexameric and decameric E. coli proteins.

A 3.3 MDa macromolecular cage between two Escherichia coli proteins with seemingly incompatible symmetries-the hexameric AAA+ ATPase RavA and the decameric inducible lysine decarboxylase LdcI-is reconstructed by cryo-electron microscopy to 11 Å resolution. Combined with a 7.

Cryo-electron microscopy three-dimensional structure of the jumbo phage ΦRSL1 infecting the phytopathogen Ralstonia solanacearum.

ϕRSL1 jumbo phage belongs to a new class of viruses within the Myoviridae family. Here, we report its three-dimensional structure determined by electron cryo microscopy. The icosahedral capsid, the tail helical portion, and the complete tail appendage were reconstructed separately to resolutions of 9 Å, 9 Å, and 28 Å, respectively.

Early stages of carbon segregation and precipitation in a sigma = 5 (310)[001] molybdenum tilt boundary.

A [Sigma] = 5 (310)[001] tilt grain boundary in molybdenum has been annealed at high temperature in the presence of carbon and observed in high-resolution electron microscopy. The carbon is located at the grain boundary in a 1-nm slab. Two different morphologies coexist.