Autoantibody binding and unique enzyme-substrate intermediate conformation of human transglutaminase 3.

Transglutaminase 3 (TG3), the autoantigen of dermatitis herpetiformis (DH), is a calcium dependent enzyme that targets glutamine residues in polypeptides for either transamidation or deamidation modifications. To become catalytically active TG3 requires proteolytic cleavage between the core domain and two C-terminal β-barrels (C1C2). Here, we report four X-ray crystal structures representing inactive and active conformations of human TG3 in complex with a TG3-specific Fab fragment of a DH patient derived antibody.

Crystal structures of cholera toxin in complex with fucosylated receptors point to importance of secondary binding site.

Cholera is a life-threatening diarrhoeal disease caused by the human pathogen Vibrio cholerae. Infection occurs after ingestion of the bacteria, which colonize the human small intestine and secrete their major virulence factor - the cholera toxin (CT). The GM1 ganglioside is considered the primary receptor of the CT, but recent studies suggest that also fucosylated receptors such as histo-blood group antigens are important for cellular uptake and toxicity.

Specificity of Heat-Labile Enterotoxin Investigated by Single-Site Mutagenesis and Crystallography.

Diarrhea caused by enterotoxigenic (ETEC) is one of the leading causes of mortality in children under five years of age and is a great burden on developing countries. The major virulence factor of the bacterium is the heat-labile enterotoxin (LT), a close homologue of the cholera toxin. The toxins bind to carbohydrate receptors in the gastrointestinal tract, leading to toxin uptake and, ultimately, to severe diarrhea.

Crystal structure of an L chain optimised 14F7 anti-ganglioside Fv suggests a unique tumour-specificity through an unusual H-chain CDR3 architecture.

Targeted cancer immunotherapy offers increased efficacy concomitantly with reduced side effects. One antibody with promising clinical potential is 14F7, which specifically recognises the NeuGc GM3 ganglioside. This antigen is found in the plasma membrane of a range of tumours, but is essentially absent from healthy human cells.

Histo-blood group antigens as mediators of infections.

The critical first step of a microbial infection is usually the attachment of pathogens to host cell glycans. Targets on host tissues are in particular the histo-blood group antigens (HBGAs), which are present in rich diversity in the mucus layer and on the underlying mucosa. Recent structural and functional studies have revealed significant new insight into the molecular mechanisms, explaining why individuals with certain blood groups are at increased risk of some infections.

Towards new cholera prophylactics and treatment: Crystal structures of bacterial enterotoxins in complex with GM1 mimics.

Cholera is a life-threatening disease in many countries, and new drugs are clearly needed. C-glycosidic antagonists may serve such a purpose. Here we report atomic-resolution crystal structures of three such compounds in complexes with the cholera toxin.

H, C, N backbone assignment of the human heat-labile enterotoxin B-pentamer and chemical shift mapping of neolactotetraose binding.

The major virulence factor of enterotoxigenic Escherichia coli is the heat-labile enterotoxin (LT), an AB toxin closely related to the cholera toxin. LT consists of six subunits, the catalytically active A-subunit and five B-subunits arranged as a pentameric ring (LTB), which enable the toxin to bind to the epithelial cells in the intestinal lumen. LTB has two recognized binding sites; the primary binding site is responsible for anchoring the toxin to its main receptor, the GM-ganglioside, while the secondary binding site recognizes blood group antigens.

High-Resolution Crystal Structures Elucidate the Molecular Basis of Cholera Blood Group Dependence.

Cholera is the prime example of blood-group-dependent diseases, with individuals of blood group O experiencing the most severe symptoms. The cholera toxin is the main suspect to cause this relationship. We report the high-resolution crystal structures (1.

Comprehensive analysis of blood group antigen binding to classical and El Tor cholera toxin B-pentamers by NMR.

Cholera is a diarrheal disease responsible for the deaths of thousands, possibly even hundreds of thousands of people every year, and its impact is predicted to further increase with climate change. It has been known for decades that blood group O individuals suffer more severe symptoms of cholera compared with individuals with other blood groups (A, B and AB). The observed blood group dependence is likely to be caused by the major virulence factor of Vibrio cholerae, the cholera toxin (CT).

The human homolog of Escherichia coli endonuclease V is a nucleolar protein with affinity for branched DNA structures.

Loss of amino groups from adenines in DNA results in the formation of hypoxanthine (Hx) bases with miscoding properties. The primary enzyme in Escherichia coli for DNA repair initiation at deaminated adenine is endonuclease V (endoV), encoded by the nfi gene, which cleaves the second phosphodiester bond 3' of an Hx lesion. Endonuclease V orthologs are widespread in nature and belong to a family of highly conserved proteins.

Both El Tor and classical cholera toxin bind blood group determinants.

Cholera is a disease which shows a clear blood group profile, with blood group O individuals experiencing the most severe symptoms. For a long time, the cholera toxin has been suspected to be the main culprit of this blood group dependence. Here, we show that both El Tor and classical cholera toxin B-pentamers do indeed bind blood group determinants (with equal affinities), using Surface Plasmon Resonance and NMR spectroscopy.