Escherichia coli O127 group 4 capsule proteins assemble at the outer membrane.

Enteropathogenic Escherichia coli O127 is encapsulated by a protective layer of polysaccharide made of the same strain specific O-antigen as the serotype lipopolysaccharide. Seven genes encoding capsule export functions comprise the group 4 capsule (gfc) operon. Genes gfcE, etk and etp encode homologs of the group 1 capsule secretion system but the upstream gfcABCD genes encode unknown functions specific to group 4 capsule export.

Structural basis of peptidoglycan endopeptidase regulation.

Most bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over; the latter process is mediated by PG cleavage enzymes, for example, the endopeptidases (EPs).

Structure of the capsule and lipopolysaccharide O-antigen from the channel catfish pathogen, Aeromonas hydrophila.

A hypervirulent A. hydrophila (vAh) pathotype has been identified as the etiologic agent responsible for disease outbreaks in farmed carp species and channel catfish (Ictalurus punctatus) in China and the Southeastern United States, respectively. The possible route of infection has previously been unknown; however, virulence is believed to be multifactorial, involving the production/secretion of several virulence factors, including a high molecular weight group 4 capsular polysaccharide.

Crystal Structure Of Photorespiratory Alanine:Glyoxylate Aminotransferase 1 (AGT1) From .

Photorespiration is an energetically costly metabolic pathway for the recycling of phosphoglycolate produced by the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) to phosphoglycerate. alanine:glyoxylate aminotransferase 1 (AGT1) is a peroxisomal aminotransferase with a central role in photorespiration. This enzyme catalyzes various aminotransferase reactions, including serine:glyoxylate, alanine:glyoxylate, and asparagine:glyoxylate transaminations.

Crystal structures of the amino-terminal domain of LpoA from Escherichia coli and Haemophilus influenzae.

The bacterial periplasmic protein LpoA is an outer membrane lipoprotein and an activator for the cross-linking activity of PBP1A, a bifunctional peptidoglycan synthase. Previous structures of the amino-terminal (N) domain of LpoA showed it to consist entirely of helices and loops, with at least four tetratricopeptide-like repeats. Although the previously determined orthorhombic crystal structure of the N domain of Haemophilus influenzae LpoA showed a typical curved structure with a concave groove, an NMR structure of the same domain from Escherichia coli was relatively flat.

Structural analyses of the peptidoglycan synthase activator LpoA suggest multiple conformations in solution.

In many Gram-negative bacteria, the peptidoglycan synthase PBP1A requires the outer membrane lipoprotein LpoA for constructing a functional peptidoglycan required for bacterial viability. Previously, we have shown that the C-terminal domain of LpoA (LpoA) has a highly conserved, putative substrate-binding cleft between two α/β lobes. Here, we report a 2.

Cycling of Etk and Etp phosphorylation states is involved in formation of group 4 capsule by Escherichia coli.

Capsules frequently play a key role in bacterial interactions with their environment. Escherichia coli capsules were categorized as groups 1 through 4, each produced by a distinct mechanism. Etk and Etp are members of protein families required for the production of group 1 and group 4 capsules.

Improved X-ray diffraction from Bacillus megaterium penicillin G acylase crystals through long cryosoaking dehydration.

Penicillin G acylase from Bacillus megaterium (BmPGA) is currently used in the pharmaceutical industry as an alternative to PGA from Escherichia coli (EcPGA) for the hydrolysis of penicillin G to produce 6-aminopenicillanic acid (6-APA), a penam nucleus for semisynthetic penicillins. Despite the significant differences in amino-acid sequence between PGAs from Gram-positive and Gram-negative bacteria, a representative PGA structure of Gram-positive origin has never been reported. In this study, crystallization and diffraction studies of BmPGA are described.

The crystal structure of Escherichia coli group 4 capsule protein GfcC reveals a domain organization resembling that of Wza.

We report the 1.9 Å resolution crystal structure of enteropathogenic Escherichia coli GfcC, a periplasmic protein encoded by the gfc operon, which is essential for assembly of group 4 polysaccharide capsule (O-antigen capsule). Presumed gene orthologs of gfcC are present in capsule-encoding regions of at least 29 genera of Gram-negative bacteria.

Structure of YraM, a protein essential for growth of Haemophilus influenzae.

Nontypeable Haemophilus influenzae is an obligate human parasite that often causes middle ear infections in children and exacerbates chronic obstructive pulmonary disorder, the fourth leading cause of death in the United States. There are no effective vaccines available for this strain. The lipoprotein YraM (gene HI1655) was identified as essential for the growth and viability of H.

Identification of an Escherichia coli operon required for formation of the O-antigen capsule.

Escherichia coli produces polysaccharide capsules that, based on their mechanisms of synthesis and assembly, have been classified into four groups. The group 4 capsule (G4C) polysaccharide is frequently identical to that of the cognate lipopolysaccharide O side chain and has, therefore, also been termed the O-antigen capsule. The genes involved in the assembly of the group 1, 2, and 3 capsules have been described, but those required for G4C assembly remained obscure.

Two substrate-targeting sites in the Yersinia protein tyrosine phosphatase co-operate to promote bacterial virulence.

YopH is a protein tyrosine phosphatase and an essential virulence determinant of the pathogenic bacterium Yersinia. Yersinia delivers YopH into infected host cells using a type III secretion mechanism. YopH dephosphorylates several focal adhesion proteins including p130Cas in human epithelial cells, resulting in disruption of focal adhesions and cell detachment from the extracellular matrix.

Solution structure and phosphopeptide binding to the N-terminal domain of Yersinia YopH: comparison with a crystal structure.

Virulence of pathogenic bacteria of the genus Yersinia requires the injection of six effector proteins into the cytoplasm of host cells. The amino-terminal domain of one of these effectors, the tyrosine phosphatase YopH, is essential for translocation of YopH, as well as for targeting it to phosphotyrosine-containing substrates of the type pYxxP. We report the high-resolution solution structure of the N-terminal domain (residues 1-129) from the Yersinia pseudotuberculosis YopH (YopH-NT) in complex with N-acetyl-DEpYDDPF-NH(2), a peptide derived from an in vivo protein substrate.