Dynamic strength of the interaction between lung surfactant protein D (SP-D) and saccharide ligands

TY - JOUR

T1 - Dynamic strength of the interaction between lung surfactant protein D (SP-D) and saccharide ligands

AU - Thormann, Esben

AU - Dreyer, Jakob K

AU - Simonsen, Adam C

AU - Hansen, Per Lyngs

AU - Hansen, Søren

AU - Holmskov, Uffe

AU - Mouritsen, Ole G

N1 - Keywords: Carbohydrates; Chromatography, Affinity; Chromatography, Ion Exchange; Enzyme-Linked Immunosorbent Assay; Ligands; Lung; Microscopy, Atomic Force; Protein Binding; Pulmonary Surfactant-Associated Protein D

PY - 2007

Y1 - 2007

N2 - In order to investigate the dynamic strength of the interaction between lung surfactant protein D (SP-D) and different sugars, maltose, mannose, glucose, and galactose, we have used an atomic force microscope to monitor the interaction on a single molecule scale. The experiment is performed by measuring the rupture force when the SP-D-sugar bond is subjected to a continuously increasing force. Under these dynamic conditions, SP-D binds strongest to d-mannose and weakest to maltose and d-galactose. These results differ from equilibrium measurements wherein SP-D exhibits preference for maltose. On the basis of this finding, we propose that the binding of the disaccharide maltose to SP-D, which is energetically stronger than the binding of any of the monosacchrides, alters the structure of the binding site in a way that lowers the dynamic strength of the bond. We conclude that determining the strength of a protein-ligand bond under dynamic stress using an atomic force microscope is possibly more relevant for mimicking the actual nonequilibrium physiological situation in the lungs.

AB - In order to investigate the dynamic strength of the interaction between lung surfactant protein D (SP-D) and different sugars, maltose, mannose, glucose, and galactose, we have used an atomic force microscope to monitor the interaction on a single molecule scale. The experiment is performed by measuring the rupture force when the SP-D-sugar bond is subjected to a continuously increasing force. Under these dynamic conditions, SP-D binds strongest to d-mannose and weakest to maltose and d-galactose. These results differ from equilibrium measurements wherein SP-D exhibits preference for maltose. On the basis of this finding, we propose that the binding of the disaccharide maltose to SP-D, which is energetically stronger than the binding of any of the monosacchrides, alters the structure of the binding site in a way that lowers the dynamic strength of the bond. We conclude that determining the strength of a protein-ligand bond under dynamic stress using an atomic force microscope is possibly more relevant for mimicking the actual nonequilibrium physiological situation in the lungs.

U2 - 10.1021/bi700823k

DO - 10.1021/bi700823k

M3 - Journal article

C2 - 17915943

SN - 0006-2960

VL - 46

SP - 12231

EP - 12237

JO - Biochemistry

JF - Biochemistry

IS - 43

ER -