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Titolo:
The haemolysin-secreting ShIB protein of the outer membrane of Serratia marcescens: determination of surface-exposed residues and formation of ion-permeable pores by ShIB mutants in artificial lipid bilayer membranes
Autore:
Konninger, UW; Hobbie, S; Benz, R; Braun, V;
Indirizzi:
Univ Tubingen, D-72076 Tubingen, Germany Univ Tubingen Tubingen Germany D-72076 bingen, D-72076 Tubingen, Germany Univ Wurzburg, D-97074 Wurzburg, Germany Univ Wurzburg Wurzburg Germany D-97074 rzburg, D-97074 Wurzburg, Germany
Titolo Testata:
MOLECULAR MICROBIOLOGY
fascicolo: 6, volume: 32, anno: 1999,
pagine: 1212 - 1225
SICI:
0950-382X(199906)32:6<1212:THSPOT>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
BACTERIOPHAGE-T7 RNA-POLYMERASE; GRAM-NEGATIVE BACTERIA; ESCHERICHIA-COLI K-12; HEMOLYSIN DETERMINANT; ERYTHROCYTE-MEMBRANES; HAEMOPHILUS-DUCREYI; CRYSTAL-STRUCTURES; IRON TRANSPORT; FHUA RECEPTOR; BETA-STRANDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
48
Recensione:
Indirizzi per estratti:
Indirizzo: Braun, V Univ Tubingen, Morgenstelle 28, D-72076 Tubingen, Germany Univ Tubingen Morgenstelle 28 Tubingen Germany D-72076 , Germany
Citazione:
U.W. Konninger et al., "The haemolysin-secreting ShIB protein of the outer membrane of Serratia marcescens: determination of surface-exposed residues and formation of ion-permeable pores by ShIB mutants in artificial lipid bilayer membranes", MOL MICROB, 32(6), 1999, pp. 1212-1225

Abstract

The ShlB protein in the outer membrane of Serratia marcescens is the only protein known to be involved in secretion of the ShlA protein across the outer membrane. At the same time, ShlB converts ShlA into a haemolytic and a cytolytic toxin. Surface-exposed residues of ShlB were determined by reaction of an M2 monoclonal antibody with the M2 epitope DYKDDDDK inserted at 25sites along the entire SI IIB polypeptide. The antibody bound to the M2 epitope at 17 sites in intact cells, which indicated surface exposure of the epitope, and to 23 sites in isolated outer membranes. Two insertion mutantscontained no ShlB(M2) protein in the outer membrane. The ShlB derivatives activated and/or secreted ShlA. To gain insights into the secretion mechanism, we studied whether highly purified ShlB and ShlB deletion derivatives formed pores in artificial lipid bilayer membranes. Wild-type ShlB formed channels with very low single channel conductance that rarely assumed an openchannel configuration. In contrast, open channels with a considerably higher single channel conductance were observed with the deletion mutants ShlB(Delta 65-186), ShlB(Delta 87-153), and ShlB(Delta 126-200). ShlB(Delta 126-200) frequently formed permanently open channels, whereas the conductance caused by ShlB(Delta 65-186) and ShlB(Delta 87-153) did not assume a stationary value, but fluctuated rapidly between open and closed configurations. The results demonstrate the orientation of large portions of ShlB in the outer membrane and suggest that ShlB may function as a specialized pore through which ShlA is secreted.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 09:03:11