Unbinding of hyaluronan accelerates the enzymatic activity of bee hyaluronidase

Attila Iliás, Károly Liliom, Brigitte Greiderer-Kleinlercher, Stephan Reitinger, Günter Lepperdinger

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Hyaluronan (HA), a polymeric glycosaminoglycan ubiquitously present in higher animals, is hydrolyzed by hyaluronidases (HAases). Here, we used bee HAase as a model enzyme to study the HA-HAase interaction. Located in close proximity to the active center, a bulky surface loop, which appears to obstruct one end of the substrate binding groove, was found to be functionally involved in HA turnover. To better understand kinetic changes in substrate interaction, binding of high molecular weight HA to catalytically inactive HAase was monitored by means of quartz crystal microbalance technology. Replacement of the delimiting loop by a tetrapeptide interconnection increased the affinity for HA up to 100-fold, with a K D below 1 nM being the highest affinity among HA-binding proteins surveyed so far. The experimental data of HA-HAase interaction were further validated showing best fit to the theoretically proposed sequential two-site model. Besides the one, which had been shown previously in course of x-ray structure determination, a previously unrecognized binding site works in conjunction with an unbinding loop that facilitates liberation of hydrolyzed HA.

Original languageEnglish
Pages (from-to)35699-35707
Number of pages9
JournalJournal of Biological Chemistry
Issue number41
Publication statusPublished - Oct 14 2011


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Iliás, A., Liliom, K., Greiderer-Kleinlercher, B., Reitinger, S., & Lepperdinger, G. (2011). Unbinding of hyaluronan accelerates the enzymatic activity of bee hyaluronidase. Journal of Biological Chemistry, 286(41), 35699-35707. https://doi.org/10.1074/jbc.M111.263731