6533b859fe1ef96bd12b6f1f
RESEARCH PRODUCT
Putative identification of an amphipathic alpha-helical sequence in hemolysin of Escherichia coli (HlyA) involved in transmembrane pore formation.
Robert SchmittMark WylenzekChristina FischerIwan WalevRicarda ReinartzSucharit BhakdiSilvia WeisAngela ValevaIsabel SiegelNatalia HeinzTrudy M. Wassenaarsubject
StereochemistryClinical BiochemistryAmino Acid MotifsPorinsmedicine.disease_causeBiochemistryProtein Structure SecondaryHemolysin ProteinsCell Line TumormedicineAnimalsHumansLipid bilayerMolecular BiologyEscherichia colichemistry.chemical_classificationEscherichia coli ProteinsRTX toxinMutagenesisErythrocyte MembraneHemolysinTransmembrane proteinAmino acidchemistryMutant ProteinsRabbitsCysteinedescription
Abstract Escherichia coli hemolysin is a pore-forming protein belonging to the RTX toxin family. Cysteine scanning mutagenesis was performed to characterize the putative pore-forming domain of the molecule. A single cysteine residue was introduced at 48 positions within the sequence spanning residues 170–400 and labeled with the polarity-sensitive dye badan. Spectrofluorimetric analyses indicated that several amino acids in this domain are inserted into the lipid bilayer during pore formation. An amphipathic α-helix spanning residues 272–298 was identified that may line the aqueous pore. The importance of this sequence was highlighted by the introduction of two prolines at positions 284 and 287. Disruption of the helix structure did not affect binding properties, but totally abolished the hemolytic activity of the molecule.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-08-21 | Biological chemistry |