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. 2011 Sep 12;2:59. doi: 10.3389/fphys.2011.00059

Figure 5.

Figure 5

SPR interaction analysis of BMP2 binding to recombinant Tsg proteins derived from different sources. Binding of recombinant Tsg proteins to a BMP2 biosensor was analyzed using SPR. BMP2 was immobilized on a GLC-chip via amino coupling. Indicated concentrations of Tsg proteins were perfused over the biosensor surface, injection started at time point 0 with a duration of 240 s (association phase) after which only buffer was again perfused for 660 s to record the dissociation of Tsg from BMP2. (A,B). The BMP2 biosensor was perfused with varying concentrations of (A) xTsg derived from expression in insect cells or (B) xTsg produced in E. coli. (C) The different dissociation rate constants between xTsg protein derived from either a eukaryotic or a prokaryotic host is apparent from an overlay of two normalized SPR sensorgrams recorded for the interaction of different xTsg proteins (500 nM concentration) with BMP2. (D) The interaction of mTWSG1 derived from E. coli expression reveals a biphasic interaction with BMP2. The binding kinetics following a slow association and a slow dissociation yields an equilibrium binding constant very similar to that of xTsg produced in bacteria.