Disease relevance of ompT

• Accordingly, we show that the presence of an F' episome results in increased resistance to the antimicrobial peptide protamine both in ompT mutants and in wild-type E. coli cells [1].
• These results indicate that the lack of OmpT protease confers upon Shigella the ability to spread into adjacent epithelial cells [2].
• Proteolysis of bacteriophage phi X174 prohead accessory protein gpB by Escherichia coli OmpT protease is not essential for phage maturation in vivo [3].
• Comparison of Escherichia coli K-12 outer membrane protease OmpT and Salmonella typhimurium E protein [4].
• Hyperproduction of a recombinant fusion protein of Staphylococcus aureus V8 protease in Escherichia coli and its processing by OmpT protease to release an active V8 protease derivative [5].

High impact information on ompT

• We identified a putative binding site for lipopolysaccharide, a molecule that is essential for OmpT activity [6].
• OmpT from Escherichia coli belongs to a family of highly homologous outer membrane proteases, known as omptins, which are implicated in the virulence of several pathogenic Gram-negative bacteria [6].
• Crystal structure of the outer membrane protease OmpT from Escherichia coli suggests a novel catalytic site [6].
• Here we present the crystal structure of OmpT, which shows a 10-stranded antiparallel beta-barrel that protrudes far from the lipid bilayer into the extracellular space [6].
• Using a synthetic substrate with these characteristics, we enriched Escherichia coli expressing the serine protease OmpT from cells expressing an inactive OmpT variant by over 5,000-fold in a single round [7].

Chemical compound and disease context of ompT

• Five molecular dynamics simulations (total duration >25 ns) have been performed on the Escherichia coli outer membrane protease OmpT embedded in a dimyristoylphosphatidylcholine lipid bilayer [8].
• Identification of active site serine and histidine residues in Escherichia coli outer membrane protease OmpT [9].
• Lipopolysaccharide regions involved in the activation of Escherichia coli outer membrane protease OmpT [10].

Biological context of ompT

• The protease that degrades them under denaturing conditions was identified as OmpT on the basis of substrate specificity, inhibitor profile, and confirmation that its N-terminal sequence is identical with that of OmpT [11].
• The deduced amino acid sequence of SopA exhibits 60% identity with those of the OmpT and OmpP outer membrane proteases of Escherichia coli [12].
• A recombinant plasmid carrying the ompT gene enables these deletion strains to synthesize OmpT and converts them to a protease-positive phenotype [13].
• Expression of gafD from the cloned gaf gene cluster in DegP-, Lon-, and OmpT-deficient recombinant strains did not significantly decrease the formation of DeltaGafD [14].
• The peptide bond whose hydrolysis would remove eight residues is a typical target for the E. coli protease OmpT [15].

Anatomical context of ompT

• After fusion to pelB, dsbA or ompT signal peptides no recombinant product could be obtained in the periplasm using the T7 promoter [16].
• Exchange of the natural signal peptide by the bacterial signal peptides of pclB or OmpT proteins considerably increased the level of expression and, as the natural signal peptide, targeted the protein to the membranes [17].
• The enzyme was overexpressed without its signal sequence in E. coli using a T7 system, resulting in the accumulation of OmpT as inclusion bodies [18].
• PgtE of Salmonella enterica and OmpT of Escherichia coli have been shown to degrade cationic antimicrobial peptides from epithelial cells or macrophages [19].
• Plasmids were constructed encoding 8 or 53 repeats of the NANP (Asp-Ala-Asp-Pro) tetrapeptide, which is the main B cell epitope of the Plasmodium falciparum circumsporozoitic protein (CSP), fused to the the MisL beta-domain and including the recognition cleavage sequence from the E. coli OmpT surface protease [20].

Associations of ompT with chemical compounds

• To facilitate further characterization of this proteolytic activity, we have optimized a system to extract and assay OmpT under denaturing conditions using a soluble substrate, rabbit muscle creatine kinase [11].
• An amino acid switch (Gly281-->Arg) within the "hinge" region of the tryptophan synthase beta subunit creates a novel cleavage site for the OmpT protease and selectively diminishes affinity toward a specific monoclonal antibody [21].
• Proteolysis of FadD by OmpT was altered by the presence of oleate or ATP, both of which are ligands for the fatty acyl-CoA synthetase [22].
• We propose that OmpT is a novel serine protease with Ser(99) as the active site nucleophile and His(212) as general base [9].
• By comparing their amino acid sequences, protease VII and OmpT, which specifically cleaves ferric enterobactin receptor protein, were found to be identical [23].

Analytical, diagnostic and therapeutic context of ompT

• Titration of OmpT with LPS and determining the resulting OmpT activity with a fluorimetric assay yielded a dissociation constant of 10-4 m for E. coli K-12 LPS [10].
• By protein engineering we have constructed an IF2 mutant Lys289-greater than Met and shown that the IF2 gamma cleavage site in this mutant protein is insensitive to cleavage by OmpT [24].
• OmpT proteolysis of E. coli initiation factor IF2. Elimination of a cleavage site by site-directed mutagenesis [24].

References