Lipopolysaccharide (LPS) is the major outer leaflet constituent of the Gram-negative outer membrane (OM) bilayer. A bipartite protein complex of LptD and LptE assembles LPS into the OM. It has been established that LptE assists folding and assembly of its β-barrel partner LptD, yet reported biochemical evidence suggested additional LptE functions. Here, we isolated dominant negative lptE mutati...

Department of Biochemistry Stanford University, 279 Campus Drive West, Stanford CA 94305, USA The (b/a)8 barrel is the most commonly occurring fold among enzymes. A key step towards rationally engineering (b/a)8 barrel proteins is to understand their underlying structural organization and folding energetics. Using misincorporation proton–alkyl exchange (MPAX), a new tool for solution structural...

Elucidating neuronal circuits and their plasticity in the cerebral cortex is one of the important questions in neuroscience research. Here we report novel axonal trajectories and their plasticity in the mouse somatosensory barrel cortex. We selectively visualized layer 2/3 neurons using in utero electroporation and examined the axonal trajectories of layer 2/3 neurons. We found that the axons o...

We report the biochemical and biophysical characterization of outer membrane protein X (OmpX), an eight-stranded transmembrane β-barrel from E. coli, and compare the barrel behavior with a mutant devoid of methionine residues. Transmembrane outer membrane proteins of bacterial origin are known to display high tolerance to sequence rearrangements and mutations. Our studies with the triple mutant...

Tubby-like proteins (TLPs), which have a highly conserved β barrel tubby domain, have been found to be associated with some animal-specific characteristics. In the plant kingdom, more than 10 TLP family members were identified in Arabidopsis, rice and maize, and they were found to be involved in responses to stress. The publication of the apple genome makes it feasible to systematically study t...

Attachment invasion locus (Ail) protein of Yersinia pestis is a crucial outer membrane protein for host invasion and determines bacterial survival within the host. Despite its importance in pathogenicity, surprisingly little is known on Ail biophysical properties. We investigate the contribution of micelle concentrations and interface tryptophans on the Ail β-barrel refolding and unfolding proc...

We briefly discuss recent progress in computational characterization of the sequence and structural properties of β-barrel membrane properties. We discuss the emerging concept of weakly stable regions in β-barrel membrane proteins, computational methods to identify these regions and mechanisms adopted by β-barrel membrane proteins in nature to stabilize them. We further discuss computational me...

In the barrel cortex, several features of single-whisker stimuli are organized in functional maps. The barrel cortex also encodes spatio-temporal correlation patterns of multi-whisker inputs, but so far the cortical mapping of neurons tuned to such input statistics is unknown. Here we report that layer 2/3 of the rat barrel cortex contains an additional functional map based on neuronal tuning t...

The neocortex is thought to be organized into functional columns of neurons, each of which processes an element of a larger representation. In the barrel cortex, the thalamic input to the column preferentially terminates in a barrel. To study the extent and nature of functional connections between columns, we measured the degree to which whisker responses are relayed between columns in the barr...

Abstract Aiming at the system level vibration problem caused by strong impact load during tank firing, is divided into several levels according to transmission path, such as barrel, cradle, turret, seat ring, car body and wheel. The multi-level response characteristics of firing are obtained arranging acceleration sensors typical positions each level. Based on time domain analysis method, wheel...