Protein secretion in gram-negative bacteria: transport across the outer membrane involves common mechanisms in different bacteria.
The xcp genes are required for protein secretion by Pseudomonas aeruginosa. They are involved in the second step of the process, i.e. the translocation across the outer membrane, after the exoproteins have reached the periplasm in a signal peptide dependent fashion. The nucleotide sequence of a 2.5 kb DNA fragment containing xcp genes showed at least two complete open reading frames, potentially encoding proteins with molecular weights of 41 and 19 kd. Products with these apparent molecular weights were identified after expression of the DNA fragment in vitro and in vivo. Subcloning and complementation experiments showed that both proteins are required for secretion. The two products are located in the inner membrane and share highly significant homologies with the PulL and PulM proteins which are required for the specific secretion of pullulanase in Klebsiella pneumoniae. These homologies reveal the existence of a common mechanism for protein secretion in Pseudomonas aeruginosa and Klebsiella pneumoniae.
Filloux
A
A
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
Bally
M
M
Ball
G
G
Akrim
M
M
Tommassen
J
J
Lazdunski
A
A
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics*; D001482:Base Composition; D001483:Base Sequence; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D015183:Restriction Mapping
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C066761:xcpY protein, Pseudomonas aeruginosa; C066762:xcpZ protein, Pseudomonas aeruginosa