Structure of the lnlB leucine-rich repeats, a domain that triggers host cell invasion by the bacterial pathogen L. monocytogenes.
The L. monocytogenes protein lnlB activates phosphoinositide 3-kinase and induces phagocytosis in several mammalian cell types. The 1.86 A resolution X-ray crystal structure of the leucine-rich repeat domain of lnlB that is both necessary and sufficient to induce phagocytosis is presented here. The structure supports a crucial role for calcium in host cell invasion by L. monocytogenes and supplies a rationale for its function. Calciums are bound to the protein in an unusually exposed manner that suggests that the metals may act as a bridge between lnlB and mammalian cell surface receptors. The structure also identifies surfaces on the curved and elongated molecule that may constitute additional interaction sites in forming a bacterial-mammalian signaling complex.
Marino
M
M
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0314, USA.
Braun
L
L
Cossart
P
P
Ghosh
P
P
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D007930:Leucine; D008089:Listeria monocytogenes / Q000472:pathogenicity / Q000502:physiology*; D008088:Listeriosis / Q000382:microbiology*; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D001426:Bacterial Proteins; D008565:Membrane Proteins; C095768:inlB protein, Listeria monocytogenes; D007930:Leucine