A method for facile production of variable lymphocyte receptors using SHuffle Escherichia coli.

Variable lymphocyte receptors (VLRs) are the antigen receptors of jawless vertebrates such as lamprey. VLRs are of growing biotechnological interest for their ability to bind certain antigenic targets with higher affinity than traditional immunoglobulins. However, VLRs are disulfide-bonded proteins that are often challenging to produce requiring genetic modifications, fusion partners, non-scalable host cell lines or inclusion body formation and refolding.

The High-Resolution Structure of a Variable Lymphocyte Receptor From Petromyzon marinus Capable of Binding to the Brain Extracellular Matrix.

Variable lymphocyte receptors (VLRs) are antigen receptors derived from the adaptive immune system of jawless vertebrates such as lamprey ( Petromyzon marinus ). First discovered in 2004, VLRs have been the subject of numerous biochemical and structural investigations. Due to their unique antigen binding properties, VLRs have been leveraged as possible drug delivery agents.

Biosynthesis of Cytidine Diphosphate-6-d-Glucitol for the Capsular Polysaccharides of .

is a Gram-negative pathogenic bacterium commonly found in chickens and is the leading cause of human diarrheal disease worldwide. The various serotypes of produce structurally distinct capsular polysaccharides (CPSs) on the exterior surfaces of the cell wall. The capsular polysaccharide from serotype HS:5 is composed of a repeating sequence of d--d--heptose and d-glucitol-6-phosphate.

Structural analysis of a bacterial UDP-sugar 2-epimerase reveals the active site architecture before and after catalysis.

The sugar, 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid, was first identified ∼40 years ago in the O-antigen of Pseudomonas aeruginosa O:3,a,d. Since then, it has been observed on the O-antigens of various pathogenic Gram-negative bacteria including Bordetella pertussis, Escherichia albertii, and Pseudomonas mediterranea. Previous studies have established that five enzymes are required for its biosynthesis beginning with uridine dinucleotide (UDP)-N-acetyl-d-glucosamine (UDP-GlcNAc).

Characterization of a novel inhibitor for the New Delhi metallo-β-lactamase-4: Implications for drug design and combating bacterial drug resistance.

The bacterial metallo-β-lactamases (MBLs) catalyze the inactivation of β-lactam antibiotics. Identifying novel pharmacophores remains crucial for the clinical development of additional MBL inhibitors. Previously, 1-hydroxypyridine-2(1H)-thione-6-carboxylic acid, hereafter referred to as 1,2-HPT-6-COOH, was reported as a low cytotoxic nanomolar β-lactamase inhibitor of Verona-integron-encoded metallo-β-lactamase 2, capable of rescuing β-lactam antibiotic activity.

Bifunctional Epimerase/Reductase Enzymes Facilitate the Modulation of 6-Deoxy-Heptoses Found in the Capsular Polysaccharides of .

is a human pathogen and the leading cause of food poisoning in the United States and Europe. Surrounding the exterior surface of this bacterium is a capsular polysaccharide (CPS) that consists of a repeating sequence of common and unusual carbohydrate segments. At least 10 different heptose sugars have thus far been identified in the various strains of .

Investigation of the enzymes required for the biosynthesis of 2,3-diacetamido-2,3-dideoxy-d-glucuronic acid in Psychrobacter cryohalolentis K5.

Psychrobacter cryohalolentis K5 is a Gram-negative bacterium first isolated from Siberian permafrost in 2006. It has a complex O-antigen containing l-rhamnose, d-galactose, two diacetamido-sugars, and one triacetamido-sugar. The biosynthetic pathway for one of the diacetamido-sugars, namely 2,3-diacetamido-2,3-dideoxy-d-glucuronic acid, is presently unknown.

C3- and C3/C5-Epimerases Required for the Biosynthesis of the Capsular Polysaccharides from .

is a human pathogen and one of the leading causes of food poisoning in Europe and the United States. The outside of the bacterium is coated with a capsular polysaccharide that assists in the evasion of the host immune system. Many of the serotyped strains of contain a 6-deoxy-heptose moiety that is biosynthesized from GDP-d--d--heptose by the successive actions of a 4,6-dehydratase, a C3/C5-epimerase, and a C4-reductase.

Reaction Mechanism and Three-Dimensional Structure of GDP-d-glycero-α-d-manno-heptose 4,6-Dehydratase from .

is a human pathogen and a leading cause of food poisoning in the United States and Europe. Surrounding the outside of the bacterium is a carbohydrate coat known as the capsular polysaccharide. Various strains of have different sequences of unusual sugars and an assortment of decorations.

Structure and function of an N-acetyltransferase from the human pathogen Acinetobacter baumannii isolate BAL_212.

Acinetobacter baumannii is a Gram-negative bacterium commonly found in soil and water that can cause human infections of the blood, lungs, and urinary tract. Of particular concern is its prevalence in health-care settings where it can survive on surfaces and shared equipment for extended periods of time. The capsular polysaccharide surrounding the organism is known to be the major contributor to virulence.

4-Deoxy-4-fluoro-GalNAz (4FGalNAz) Is a Metabolic Chemical Reporter of O-GlcNAc Modifications, Highlighting the Notable Substrate Flexibility of O-GlcNAc Transferase.

Bio-orthogonal chemistries have revolutionized many fields. For example, metabolic chemical reporters (MCRs) of glycosylation are analogues of monosaccharides that contain a bio-orthogonal functionality, such as azides or alkynes. MCRs are metabolically incorporated into glycoproteins by living systems, and bio-orthogonal reactions can be subsequently employed to install visualization and enrichment tags.

Biochemical investigation of an N-acetyltransferase from Helicobacter pullorum.

N-acetylated sugars are often found, for example, on the lipopolysaccharides of Gram-negative bacteria, on the S-layers of Gram-positive bacteria, and on the capsular polysaccharides. Key enzymes involved in their biosynthesis are the sugar N-acetyltransferases. Here, we describe a structural and functional analysis of one such enzyme from Helicobacter pullorum, an emerging pathogen that may be associated with gastroenteritis and gallbladder and liver diseases.

Investigation of the enzymes required for the biosynthesis of an unusual formylated sugar in the emerging human pathogen Helicobacter canadensis.

It is now well established that the Gram-negative bacterium, Helicobacter pylori, causes gastritis in humans. In recent years, it has become apparent that the so-called non-pylori Helicobacters, normally infecting pigs, cats, and dogs, may also be involved in human pathology via zoonotic transmission. Indeed, more than 30 species of non-pylori Helicobacters have been identified thus far.

Characterization of an aminotransferase from Acanthamoeba polyphaga Mimivirus.

Acanthamoeba polyphaga Mimivirus, a complex virus that infects amoeba, was first reported in 2003. It is now known that its DNA genome encodes for nearly 1,000 proteins including enzymes that are required for the biosynthesis of the unusual sugar 4-amino-4,6-dideoxy-d-glucose, also known as d-viosamine. As observed in some bacteria, the pathway for the production of this sugar initiates with a nucleotide-linked sugar, which in the Mimivirus is thought to be UDP-d-glucose.

Biosynthesis of d--l--Heptose in the Capsular Polysaccharides of .

is the leading cause of food poisoning in the United States and Europe. The exterior cell surface of is coated with a capsular polysaccharide (CPS) that is essential for the maintenance and integrity of the bacterial cell wall and evasion of the host immune response. The identity and sequences of the monosaccharide components of the CPS are quite variable and dependent on the specific strain of .

Characterization of two enzymes from Psychrobacter cryohalolentis that are required for the biosynthesis of an unusual diacetamido-d-sugar.

Psychrobacter cryohalolentis strain K5 is a Gram-negative organism first isolated in 2006. It has a complex O-antigen that contains, in addition to l-rhamnose and d-galactose, two diacetamido- and a triacetamido-sugar. The biochemical pathways for the production of these unusual sugars are presently unknown.

[Steroids in infection medicine].

Corticosteroids have been found as useful adjunctive therapy in patients with various infections and hyperinflammation-associated disease. They are recommended in practice guidelines for patients with tuberculous and pneumococcal meningitis and patients with immune reconstitution syndrome associated with antiretroviral therapy. A new indication is severe COVID-19.

The high-resolution structure of a UDP-L-rhamnose synthase from Acanthamoeba polyphaga Mimivirus.

For the field of virology, perhaps one of the most paradigm-shifting events so far in the 21st century was the identification of the giant double-stranded DNA virus that infects amoebae. Remarkably, this virus, known as Mimivirus, has a genome that encodes for nearly 1,000 proteins, some of which are involved in the biosynthesis of unusual sugars. Indeed, the virus is coated by a layer of glycosylated fibers that contain d-glucose, N-acetyl-d-glucosamine, l-rhamnose, and 4-amino-4,6-dideoxy-d-glucose.

Structural Analysis of Cj1427, an Essential NAD-Dependent Dehydrogenase for the Biosynthesis of the Heptose Residues in the Capsular Polysaccharides of .

Many strains of display modified heptose residues in their capsular polysaccharides (CPS). The precursor heptose was previously shown to be GDP-d--α-d--heptose, from which a variety of modifications of the sugar moiety have been observed. These modifications include the generation of 6-deoxy derivatives and alterations of the stereochemistry at C3-C6.

Biochemical analysis of a sugar 4,6-dehydratase from Acanthamoeba polyphaga Mimivirus.

The exciting discovery of the giant DNA Mimivirus in 2003 challenged the conventional description of viruses in a radical way, and since then, dozens of additional giant viruses have been identified. It has now been demonstrated that the Mimivirus genome encodes for the two enzymes required for the production of the unusual sugar 4-amino-4,6-dideoxy-d-glucose, namely a 4,6-dehydratase and an aminotransferase. In light of our long-standing interest in the bacterial 4,6-dehydratases and in unusual sugars in general, we conducted a combined structural and functional analysis of the Mimivirus 4,6-dehydratase referred to as R141.

Misannotations of the genes encoding sugar N-formyltransferases.

Tens of thousands of bacterial genome sequences are now known due to the development of rapid and inexpensive sequencing technologies. An important key in utilizing these vast amounts of data in a biologically meaningful way is to infer the function of the proteins encoded in the genomes via bioinformatics techniques. Whereas these approaches are absolutely critical to the annotation of gene function, there are still issues of misidentifications, which must be experimentally corrected.

Structural and Functional Characterization of YdjI, an Aldolase of Unknown Specificity in K12.

The gene cluster is found in 80% of sequenced genomes and other closely related species in the human microbiome. On the basis of the annotations of the enzymes located in this cluster, it is expected that together they catalyze the catabolism of an unknown carbohydrate. The focus of this investigation is on YdjI, which is in the gene cluster of K-12.

Investigation of a sugar N-formyltransferase from the plant pathogen Pantoea ananatis.

Pantoea ananatis is a Gram-negative bacterium first recognized in 1928 as the causative agent of pineapple rot in the Philippines. Since then various strains of the organism have been implicated in the devastation of agriculturally important crops. Some strains, however, have been shown to function as non-pathogenic plant growth promoting organisms.

[Opportunistic infections: What's new?].

Guidelines from 3 clinical societies and peer-reviewed publications have been reviewed for recent changes in the management of opportunistic infections. Trimethoprim and sulfamethoxazol administered intravenously is an option to treat cerebral toxoplasmosis if oral therapy is not feasible. CD4 T cell cut-off for starting prophylaxis with trimethoprim and sulfamethoxazole is now 200/µl.