SPR studies of carbohydrate-protein interactions: signal enhancement of low-molecular-mass analytes by organoplatinum(II)-labeling.
The relatively insensitive surface plasmon resonance (SPR) signal detection of low-molecular-mass analytes that bind with weak affinity to a protein--for example, carbohydrate-lectin binding--is hampering the use of biosensors in interaction studies. In this investigation, low-molecular-mass carbohydrates have been labeled with an organoplatinum(II) complex of the type [PtCl(NCN-R)]. The attachment of this complex increased the SPR response tremendously and allowed the detection of binding events between monosaccharides and lectins at very low analyte concentrations. The platinum atom inside the organoplatinum(II) complex was shown to be essential for the SPR-signal enhancement. The organoplatinum(II) complex did not influence the specificity of the biological interaction, but both the signal enhancement and the different binding character of labeled compounds when compared with unlabeled ones makes the method unsuitable for the direct calculation of biologically relevant kinetic parameters. However, the labeling procedure is expected to be of high relevance for qualitative binding studies and relative affinity ranking of small molecules (not restricted only to carbohydrates) to receptors, a process of immense interest in pharmaceutical research.
Beccati
Daniela
D
Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Halkes
Koen M
KM
Batema
Guido D
GD
Guillena
Gabriela
G
Carvalho de Souza
Adriana
A
van Koten
Gerard
G
Kamerling
Johannis P
JP
D002241:Carbohydrates / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry; D009944:Organoplatinum Compounds / Q000737:chemistry*; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D020349:Surface Plasmon Resonance
D002241:Carbohydrates; D037102:Lectins; D009844:Oligosaccharides; D009944:Organoplatinum Compounds; D011506:Proteins