Journal Article

PUBDB-2015-01339

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Oligomerization Inhibits Legionella Pneumophila PlaB Phospholipase A Activity

Kuhle, K. (Corresponding Author)>Extern* ; Krausze, J.>Extern* ; Curth, U. ; Roessle, M.>Extern*EMBL* ; Heuner, K. ; Lang, C.>Extern* ; Flieger, A.

2014
Soc. Bethesda, Md.

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Please use a persistent id in citations: doi:10.1074/jbc.M114.573196

Abstract: The intracellularly replicating lung pathogen Legionella pneumophila consists of an extraordinary variety of phospholipases, including at least 15 different phospholipases A (PLA). Among them, PlaB, the first characterized member of a novel lipase family, is a hemolytic virulence factor that exhibits the most prominent PLA activity in L. pneumophila. We analyzed here protein oligomerization, the importance of oligomerization for activity, addressed further essential regions for activity within the PlaB C terminus, and the significance of PlaB-derived lipolytic activity for L. pneumophila intracellular replication. We determined by means of analytical ultracentrifugation and small angle x-ray scattering analysis that PlaB forms homodimers and homotetramers. The C-terminal 5, 10, or 15 amino acids, although the individual regions contributed to PLA activity, were not essential for protein tetramerization. Infection of mouse macrophages with L. pneumophila wild type, plaB knock-out mutant, and plaB complementing or various mutated plaB-harboring strains showed that catalytic activity of PlaB promotes intracellular replication. We observed that PlaB was most active in the lower nanomolar concentration range but not at or only at a low level at concentration above 0.1 $\mu M$ where it exists in a dimer/tetramer equilibrium. We therefore conclude that PlaB is a virulence factor that, on the one hand, assembles in inactive tetramers at micromolar concentrations. On the other hand, oligomer dissociation at nanomolar concentrations activates PLA activity. Our data highlight the first example of concentration-dependent phospholipase inactivation by tetramerization, which may protect the bacterium from internal PLA activity, but enzyme dissociation may allow its activation after export.

Note: (c) by The American Society for Biochemistry and Molecular Biology, Inc. Post referee full text in progress.

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Contributing Institute(s):

1. EMBL (EMBL)
2. DOOR-User (DOOR)

Research Program(s):

1. DORIS Beamline D1.2 (POF2-54G13) (POF2-54G13)
2. 6G3 - PETRA III (POF3-622) (POF3-622)

Experiment(s):

1. DORIS Beamline D1.2 (DORIS III)
2. PETRA Beamline P12 (PETRA III)

Appears in the scientific report 2014

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Database coverage:
; BIOSIS Previews ; Current Contents - Life Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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