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.
The Parkinson's disease is a neurodegenerative disorder with a range of symptoms such as slowness, rigidity, resting tremor (trembling), and an impairment of postural balance leading to disturbance of gait and falling. Continuous exercises are an effective strategy to maintain the patient's movement abilities, slowing down the progression of the disease. Self-directed exercises in addition to supervised physiotherapy sessions are not only beneficial, but necessary. This paper presents an approach to support Parkinson's disease patients in their daily exercises using the playful context of different motionbased digital games adapted from physiotherapy.