title: S-layer protein transport across the cell wall of Corynebacterium glutamicum: in vivo kinetics and energy requirements.
abstract: Corynebacteria are Gram-positive bacteria with a very peculiar cell envelope structure as it is constituted of an inner membrane and an outer membrane-like structure. Protein secretion in Corynebacterium glutamicum was studied in vivo, using the S-layer protein PS2 as a model. We show that different variants of PS2 protein are exported through the whole cell envelope with a half-life ranging between 2 and 4 min, by a two-step mechanism. The first step, which is over after about 1.5 min, is ATP- and proton motive force-dependent and may correspond to translocation across the inner membrane via the 'Sec' machinery. The second step, across the cell wall and the outer mycolate layer, is rapid but independent of energy sources. This very efficient secretion process across the mycolate layer raises the question of the existence in this layer of a specific machinery.
authors.affiliation: Laboratoire de Biotechnologie des Microorganismes d'Intérêt Industriel, Institut de Génétique et Microbiologie, CNRS UMR 8621, Université Paris XI, 91405 Cedex, Orsay, France.
authors.forename: C
authors.initials: C
authors.lastname: Houssin
authors.forename: D T
authors.initials: DT
authors.lastname: Nguyen
authors.forename: G
authors.initials: G
authors.lastname: Leblon
authors.forename: N
authors.initials: N
authors.lastname: Bayan
mesh_terms: D001426:Bacterial Proteins / Q000145:classification / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000819:agonists / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D003352:Corynebacterium / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins; D008957:Models, Genetic; D021381:Protein Transport; D019810:Sodium Azide / Q000819:agonists / Q000378:metabolism; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D019810:Sodium Azide