The PPIase active site of Legionella pneumophila Mip protein is involved in the infection of eukaryotic host cells

Jürgen H Helbig; Bettina König; Henry Knospe; Birgit Bubert; Chao Yu; Christian P Lück; Alan Riboldi-Tunnicliffe; Rolf Hilgenfeld; Enno Jacobs; Jörg Hacker; Gunter Fischer

doi:10.1515/BC.2003.013

The PPIase active site of Legionella pneumophila Mip protein is involved in the infection of eukaryotic host cells

Biol Chem. 2003 Jan;384(1):125-37. doi: 10.1515/BC.2003.013.

Authors

Jürgen H Helbig¹, Bettina König, Henry Knospe, Birgit Bubert, Chao Yu, Christian P Lück, Alan Riboldi-Tunnicliffe, Rolf Hilgenfeld, Enno Jacobs, Jörg Hacker, Gunter Fischer

Affiliation

¹ Medizinische Fakultät der TU Dresden, Institut für Medizinische Mikrobiologie und Hygiene, Fetscherstr. 74, D-01307 Dresden, Germany.

PMID: 12674506
DOI: 10.1515/BC.2003.013

Abstract

We analysed eight monoclonal antibodies (mAbs) directed against the Mip (macrophage infectivity potentiator) protein, a virulence factor of the intracellular pathogen Legionella pneumophila. Mip belongs to the FK506-binding proteins (FKBPs) and exhibits peptidyl prolyl cis/trans isomerase (PPIase) activity. Five of the mAbs recognised epitopes in the C-terminal, FKBP-homologous domain of Mip, which is highly conserved among all Legionella species. Upon immunological binding to Mip, all but one of these mAbs caused inhibition of the PPIase activity in vitro. mAb binding to the N-terminal domain of Mip did not influence its enzymatic activity. All but one of the PPIase inhibiting mAbs were able to significantly inhibit the early establishment and initiation of an intracellular infection of the bacteria in Acanthamoeba castellanii, the natural host, and in the human phagocytic cell line U937. These data demonstrate for the first time that for the virulence-enhancing property of the L. pneumophila Mip protein, an intact active site of the enzyme is an essential requirement.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acanthamoeba / microbiology
Amino Acid Substitution / genetics
Animals
Antibodies, Monoclonal / chemistry
Antigens, Surface / genetics
Bacterial Proteins
Binding Sites
Binding Sites, Antibody / genetics
Cell Line
Culture Media
Electrophoresis, Polyacrylamide Gel
Enzyme-Linked Immunosorbent Assay
Epitope Mapping
Escherichia coli / metabolism
Escherichia coli Proteins
Eukaryotic Cells / microbiology
Humans
Immunoblotting
Immunoglobulin G / genetics
Immunophilins / chemistry*
Kinetics
Legionella pneumophila / enzymology*
Legionella pneumophila / pathogenicity
Legionnaires' Disease / enzymology
Legionnaires' Disease / microbiology*
Macrophages / microbiology
Membrane Proteins / chemistry*
Peptidylprolyl Isomerase / chemistry*
Plasmids / genetics
Surface Plasmon Resonance

Substances

Antibodies, Monoclonal
Antigens, Surface
Bacterial Proteins
Culture Media
Escherichia coli Proteins
Immunoglobulin G
Membrane Proteins
Immunophilins
Mip protein, Legionella pneumophila
Peptidylprolyl Isomerase
FkpA protein, E coli