X-ray and neutron small-angle scattering analysis of the complex formed by the met receptor and the Listeria monocytogenes invasion protein InlB

JOURNAL OF MOLECULAR BIOLOGY

卷:377

Article

Niemann, Hartmut H.^1,2  Petoukhov, Maxim V.^3,4  Hartlein, Michael⁵  Moulin, Martine⁵  Gherardi, Ermanno⁶  Timmins, Peter⁵  Heinz, Dirk W.¹  Svergun, Dmitri I.^3,4 

[1] Helmholtz Ctr Infect Res, Div Struct Biol, D-38124 Braunschweig, Germany

[2] Univ Bielefeld, Dept Chem, D-33615 Bielefeld, Germany

[3] European Mol Biol Lab, D-22603 Hamburg, Germany

[4] Russian Acad Sci, Inst Crystallog, Moscow 117333, Russia

[5] Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France

[6] MRC Ctr, Cambridge CB2 2QH, England

关键词: complex formation;    rigid-body modeling;    neutron scattering;    receptor tyrosine kinase;    small-angle scattering;   

DOI  :  10.1016/j.jmb.2008.01.027

来源: Elsevier

【 摘 要 】

The Listeria monocytogenes surface protein InIB binds to the extracellular domain of the human receptor tyrosine kinase Met, the product of the c-met proto-oncogene. InlB binding activates the Met receptor, leading to uptake of Listeria into normally nonphagocytic host cells. The N-terminal half of InIB (InlB(321)) is sufficient for Met binding and activation. The complex between this Met-binding domain of InIB and various constructs of the Met ectodomain was characterized by size exclusion chromatography and dynamic light scattering, and structural models were built using small-angle X-ray scattering and small-angle neutron scattering. Although most receptor tyrosine kinase ligands induce receptor dimerization, InlB(321) consistently binds the Met ectodomain with a 1:1 stoichiometry. A construct comprising the Sema and PSI domains of Met, although sufficient to bind the physiological Met ligand hepatocyte growth factor/scatter factor, does not form a complex with InlB(321) in solution, highlighting the importance of Met Ig domains for InIB binding. Small-angle X-ray scattering and small-angle neutron scattering measurements of ligand and receptor, both free and in complex, reveal an elongated shape for the receptor. The four Ig domains form a bent, rather than a fully extended, conformation, and InlB(321) binds to Sema and the first Ig domain of Met, in agreement with the recent crystal structure of a smaller Met fragment in complex with InlB(321), These results call into question whether receptor dimerization is the basic underlying event in InlB(321)-mediated Met activation and demonstrate differences in the mechanisms by which the physiological ligand hepatocyte growth factor/scatter factor and InlB(321) bind and activate the Met receptor. (C) 2008 Elsevier Ltd. All rights reserved.

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