Background:The cell adhesion molecule L1 plays important roles in the developing and adult nervous system. Results: L1 is cleaved by myelin basic protein (MBP) yielding a L1 fragment that promotes L1-dependent functions. Conclusion: L1 functions in the nervous system depend on MBP. Significance: Study of the L1 and MBP functions may contribute to understanding the pathogenesis of demyelinating and neurodegenerative diseases.

Although carbohydrates have been implicated in cell interactions

OqxB is an RND (Resistance-Nodulation-Division) efflux pump that has emerged as a factor contributing to the antibiotic resistance in Klebsiella pneumoniae. OqxB underwent horizontal gene transfer and is now seen in other Gram-negative bacterial pathogens including Escherichia coli, Enterobacter cloacae and Salmonella spp., further disseminating multi-drug resistance. In this study, we describe crystal structure of OqxB with n-dodecyl-β-D-maltoside (DDM) molecules bound in its substrate-binding pocket, at 1.85 Å resolution. We utilize this structure in computational studies to predict the key amino acids contributing to the efflux of fluoroquinolones by OqxB, distinct from analogous residues in related transporters AcrB and MexB. Finally, our complementation assays with mutated OqxB and minimum inhibitory concentration (MIC) experiments with clinical isolates of E. coli provide further evidence that the predicted structural features are indeed involved in ciprofloxacin efflux.