Investigation of the mechanism of binding between internalin B and heparin using surface plasmon resonance

Sybil C.Lang Hrtska, Melissa M. Kemp, Eva M. Muñoz, Omaira Azizad, Mani Banerjee, Catarina Raposo, Jyothi Kumaran, Partho Ghosh, Robert J. Linhardt

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Listeria monocytogenes, a food-borne pathogen that infects immunocompromised patients, enters and proliferates within mammalian cells by taking advantage of host cell machinery. While entry into macrophages and other phagocytic cells occurs constitutively, intracellular invasion of nonphagocytic cells, such as epithelial and endothelial cells, occurs through induced phagocytosis. Invasion of these nonphagocytic cell types is under the control of the secreted L. monocytogenes protein internalin B (InlB), which directly associates with and activates the receptor tyrosine kinase Met. Activation of Met by InlB has previously been shown to be potentiated by binding of glycosaminoglycans to the GW domains of this protein. We studied the interaction between heparin and full-length InlB as well as a truncated, functional form of InlB to understand the mode of interaction between these two molecules. InlB preferred long-chain (≥dp14) heparin oligosaccharides, and the interaction with heparin fit a complicated binding model with a dissociation constant in the nanomolar range. While there are various explanations for this complicated binding model, one supported by our data involves binding and rebinding of InIB to multiple binding sites on heparin in a positive and weakly cooperative manner. This mode is consistent with enhancement of interaction of InlB with glycosaminoglycans for activation of Met.

Original languageEnglish
Pages (from-to)2697-2706
Number of pages10
Issue number10
StatePublished - 13 Mar 2007
Externally publishedYes


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