The major outer membrane protein of Legionella pneumophila Lpg1974 shows pore-forming characteristics similar to the human mitochondrial outer membrane pore, hVDAC1

Publication date: Available online 19 May 2018 Source:Biochimica et Biophysica Acta (BBA) - Biomembranes Author(s): Farhan Younas, Nafiseh Soltanmohammadi, Oliver Knapp, Roland Benz Legionella pneumophila is an aerobic and nonspore-forming pathogenic Gram-negative bacterium of the genus Legionella. It is the causative agent of Legionnaires' disease, also known as Legionellosis. The hosts of this organism are diverse, ranging from simple water borne protozoans such as amoebae to more complex hosts such as macrophages in humans. Genome analyses have shown the presence of genes coding for eukaryotic like proteins in several Legionella species. The presence of these proteins may assist L. pneumophila in its adaptation to the eukaryotic host. We studied the characteristics of a protein (Lpg1974) of L. pneumophila that shows remarkable homologies in length of the primary sequence and for the identity/homology of many amino acids to the voltage dependent anion channel (human VDAC1, Porin 31HL) of human mitochondria. Two different forms of Lpg1974 were overexpressed in Escherichia coli and purified to homogeneity: the one containing a putative N-terminal signal sequence and one without it. Reconstituted protein containing the signal sequence formed ion-permeable pores in lipid bilayer membranes with a conductance of approximately 5.4 nS in 1 M KCl. When the predicted N-terminal signal peptide of Lpg1974 comprising an α-helical structure similar to that at the N-terminus of...
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research