uses energy taxis and a dehydrogenase enzyme for l-fucose chemotaxis.

In this study, we identify a separate role for the l-fucose dehydrogenase in l-fucose chemotaxis and demonstrate that this mechanism is not only limited to but is also present in . We now hypothesize that l-fucose energy taxis may contribute to the reduction of l-fucose-metabolizing strains of from the gastrointestinal tract of breastfed infants, selecting for isolates with increased colonization potential.

Permethylation as a strategy for high-molecular-weight polysaccharide structure analysis by nuclear magnetic resonance-Case study of Xylella fastidiosa extracellular polysaccharide.

Current practices for structural analysis of extremely large-molecular-weight polysaccharides via solution-state nuclear magnetic resonance (NMR) spectroscopy incorporate partial depolymerization protocols that enable polysaccharide solubilization in suitable solvents. Non-specific depolymerization techniques utilized for glycosidic bond cleavage, such as chemical degradation or ultrasonication, potentially generate structural fragments that can complicate complete and accurate characterization of polysaccharide structures. Utilization of appropriate enzymes for polysaccharide degradation, on the other hand, requires prior structural knowledge and optimal enzyme activity conditions that are not available to an analyst working with novel or unknown compounds.

Acetylation in Ionic Liquids Dramatically Increases Yield in the Glycosyl Composition and Linkage Analysis of Insoluble and Acidic Polysaccharides.

Glycosyl composition and linkage analyses are important first steps toward understanding the structural diversity and biological importance of polysaccharides. Failure to fully solubilize samples prior to analysis results in the generation of incomplete and poor-quality composition and linkage data by gas chromatography-mass spectrometry (GC-MS). Acidic polysaccharides also do not give accurate linkage results, because they are poorly soluble in DMSO and tend to undergo β-elimination during permethylation.

Permethylation as a Strategy for High Molecular Weight Polysaccharide Structure Analysis by NMR - Case Study of EPS.

Current practices for structure analysis of extremely large molecular weight polysaccharides via solution-state NMR spectroscopy incorporate partial depolymerization protocols that enable polysaccharide solubilization in suitable solvents. Non-specific depolymerization techniques utilized for glycosidic bond cleavage, such as chemical degradation or ultrasonication, potentially generate structure fragments that can complicate the complete characterization of polysaccharide structures. Utilization of appropriate enzymes for polysaccharide degradation, on the other hand, requires prior structure information and optimal enzyme activity conditions that are not available to the analyst working with novel or unknown compounds.

Surface Anchoring of the Kingella kingae Galactan Is Dependent on the Lipopolysaccharide O-Antigen.

Kingella kingae is a leading cause of bone and joint infections and other invasive diseases in young children. A key K. kingae virulence determinant is a secreted exopolysaccharide that mediates resistance to serum complement and neutrophils and is required for full pathogenicity.

Molecular basis for polysaccharide recognition and modulated ATP hydrolysis by the O antigen ABC transporter.

O antigens are ubiquitous protective extensions of lipopolysaccharides in the extracellular leaflet of the Gram-negative outer membrane. Following biosynthesis in the cytosol, the lipid-linked polysaccharide is transported to the periplasm by the WzmWzt ABC transporter. Often, O antigen secretion requires the chemical modification of its elongating terminus, which the transporter recognizes via a carbohydrate-binding domain (CBD).

An atypical lipoteichoic acid from elicits a broadly cross-reactive and protective immune response.

is a leading cause of food-poisoning and causes avian necrotic enteritis, posing a significant problem to both the poultry industry and human health. No effective vaccine against is currently available. Using an antiserum screen of mutants generated from a transposon-mutant library, here we identified an immunoreactive antigen that was lost in a putative glycosyltransferase mutant, suggesting that this antigen is likely a glycoconjugate.

A Common Food Glycan, Pectin, Shares an Antigen with Streptococcus pneumoniae Capsule.

We are exposed daily to many glycans from bacteria and food plants. Bacterial glycans are generally antigenic and elicit antibody responses. It is unclear if food glycans' sharing of antigens with bacterial glycans influences our immune responses to bacteria.

Structural and biophysical characterizations of HIV-1 matrix trimer binding to lipid nanodiscs shed light on virus assembly.

During the late phase of the HIV-1 replication cycle, the viral Gag polyproteins are targeted to the plasma membrane for assembly. The Gag-membrane interaction is mediated by binding of Gag's N-terminal myristoylated matrix (MA) domain to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P). The viral envelope (Env) glycoprotein is then recruited to the assembly sites and incorporated into budding particles.

Pneumococci Can Become Virulent by Acquiring a New Capsule From Oral Streptococci.

Pneumococcal conjugate vaccines have been successful, but their use has increased infections by nonvaccine serotypes. Oral streptococci often harbor capsular polysaccharide (PS) synthesis loci (cps). Although this has not been observed in nature, if pneumococcus can replace its cps with oral streptococcal cps, it may increase its serotype repertoire.

The KN-93 Molecule Inhibits Calcium/Calmodulin-Dependent Protein Kinase II (CaMKII) Activity by Binding to Ca/CaM.

Calcium/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine protein kinase that transmits calcium signals in various cellular processes. CaMKII is activated by calcium-bound calmodulin (Ca/CaM) through a direct binding mechanism involving a regulatory C-terminal α-helix in CaMKII. The Ca/CaM binding triggers transphosphorylation of critical threonine residues proximal to the CaM-binding site leading to the autoactivated state of CaMKII.

The tuberculosis necrotizing toxin is an NAD and NADP glycohydrolase with distinct enzymatic properties.

Upon host infection, secretes the tuberculosis necrotizing toxin (TNT) into the cytosol of infected macrophages, leading to host cell death by necroptosis. TNT hydrolyzes NAD in the absence of any exogenous cofactor, thus classifying it as a β-NAD glycohydrolase. However, TNT lacks sequence similarity with other NAD hydrolyzing enzymes and lacks the essential motifs involved in NAD binding and hydrolysis by these enzymes.

Structural basis for targeting avian sarcoma virus Gag polyprotein to the plasma membrane for virus assembly.

For most retroviruses, including HIV-1, binding of the Gag polyprotein to the plasma membrane (PM) is mediated by interactions between Gag's N-terminal myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P) in the PM. The Gag protein of avian sarcoma virus (ASV) lacks the -myristoylation signal but contains structural domains having functions similar to those of HIV-1 Gag. The molecular mechanism by which ASV Gag binds to the PM is incompletely understood.

The matrix domain of the Gag protein from avian sarcoma virus contains a PI(4,5)P-binding site that targets Gag to the cell periphery.

The Gag protein of avian sarcoma virus (ASV) lacks an -myristoyl (myr) group, but contains structural domains similar to those of HIV-1 Gag. Similarly to HIV-1, ASV Gag accumulates on the plasma membrane (PM) before egress; however, it is unclear whether the phospholipid PI(4,5)P binds directly to the matrix (MA) domain of ASV Gag, as is the case for HIV-1 Gag. Moreover, the role of PI(4,5)P in ASV Gag localization and budding has been controversial.

Solution Structure and Membrane Interaction of the Cytoplasmic Tail of HIV-1 gp41 Protein.

The cytoplasmic tail of gp41 (gp41CT) remains the last HIV-1 domain with an unknown structure. It plays important roles in HIV-1 replication such as mediating envelope (Env) intracellular trafficking and incorporation into assembling virions, mechanisms of which are poorly understood. Here, we present the solution structure of gp41CT in a micellar environment and characterize its interaction with the membrane.

Novel Method for Reliable Identification of Siccibacter and Franconibacter Strains: from "Pseudo-Cronobacter" to New Enterobacteriaceae Genera.

In the last decade, strains of the genera and have been misclassified as first and later Because is a serious foodborne pathogen that affects premature neonates and elderly individuals, such misidentification may not only falsify epidemiological statistics but also lead to tests of powdered infant formula or other foods giving false results. Currently, the main ways of identifying and strains are by biochemical testing or by sequencing of the gene as part of multilocus sequence typing (MLST), but in relation to these strains the former is generally highly difficult and unreliable while the latter remains expensive. To address this, we developed a fast, simple, and most importantly, reliable method for and identification based on intact-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).

Derepression of SaPIbov1 Is Independent of φNM1 Type 2 dUTPase Activity and Is Inhibited by dUTP and dUMP.

Staphylococcus aureus is an opportunistic human pathogen able to transfer virulence genes to other cells through the mobilization of S. aureus pathogenicity islands (SaPIs). SaPIs are derepressed and packaged into phage-like transducing particles by helper phages like 80α or φNM1.

Novel PCR-RFLP system based on rpoB gene for differentiation of Cronobacter species.

Bacteria from the genus Cronobacter are opportunistic foodborne pathogens that can cause severe infections. More rapid, cost-effective and reliable methods are still required for the species identification of Cronobacter spp. In this study, we present a novel PCR-RFLP-based method that uses a newly designed pair of primers for the PCR-amplification of a partial rpoB gene sequence (1635 bp).

Identification of the Calmodulin-Binding Domains of Fas Death Receptor.

The extrinsic apoptotic pathway is initiated by binding of a Fas ligand to the ectodomain of the surface death receptor Fas protein. Subsequently, the intracellular death domain of Fas (FasDD) and that of the Fas-associated protein (FADD) interact to form the core of the death-inducing signaling complex (DISC), a crucial step for activation of caspases that induce cell death. Previous studies have shown that calmodulin (CaM) is recruited into the DISC in cholangiocarcinoma cells and specifically interacts with FasDD to regulate the apoptotic/survival signaling pathway.

Diversity of O Antigens within the Genus Cronobacter: from Disorder to Order.

Cronobacter species are Gram-negative opportunistic pathogens that can cause serious infections in neonates. The lipopolysaccharides (LPSs) that form part of the outer membrane of such bacteria are possibly related to the virulence of particular bacterial strains. However, currently there is no clear overview of O-antigen diversity within the various Cronobacter strains and links with virulence.

Structural and molecular determinants of HIV-1 Gag binding to the plasma membrane.

Targeting of the Gag polyprotein to the plasma membrane (PM) for assembly is a critical event in the late phase of immunodeficiency virus type-1 (HIV-1) infection. Gag binding to the PM is mediated by interactions between the myristoylated matrix (MA) domain and PM lipids. Despite the extensive biochemical and in vitro studies of Gag and MA binding to membranes over the last two decades, the discovery of the role of phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] in Gag binding to the PM has sparked a string of studies aimed at elucidating the molecular mechanism of retroviral Gag-PM binding.

HIV: a vicTIM.

TIM proteins are known to promote viral entry into host cells. Unexpectedly, a recent study has shown that TIM proteins also inhibit HIV-1 release from the host cell by directly binding to phosphatidylserine exposed on the virus surface, providing details on a new role of TIM proteins in HIV replication.

Solution structure of calmodulin bound to the binding domain of the HIV-1 matrix protein.

Subcellular distribution of calmodulin (CaM) in human immunodeficiency virus type-1 (HIV-1)-infected cells is distinct from that observed in uninfected cells. CaM co-localizes and interacts with the HIV-1 Gag protein in the cytosol of infected cells. Although it has been shown that binding of Gag to CaM is mediated by the matrix (MA) domain, the structural details of this interaction are not known.