Konuma's present address is Suntory Foundation for Life Sciences, Wakayamadai 1-1-1, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan
Principal component analysis of chemical shift perturbation data of a multiple-ligand-binding system for elucidation of respective binding mechanism
Article first published online: 26 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
Proteins: Structure, Function, and Bioinformatics
Volume 81, Issue 1, pages 107–118, January 2013
How to Cite
Konuma, T., Lee, Y.-H., Goto, Y. and Sakurai, K. (2013), Principal component analysis of chemical shift perturbation data of a multiple-ligand-binding system for elucidation of respective binding mechanism. Proteins, 81: 107–118. doi: 10.1002/prot.24166
- Issue published online: 15 DEC 2012
- Article first published online: 26 SEP 2012
- Accepted manuscript online: 24 AUG 2012 04:50AM EST
- Manuscript Accepted: 17 AUG 2012
- Manuscript Revised: 24 JUL 2012
- Manuscript Received: 2 MAY 2012
- Japanese Ministry of Education, Science, Culture, and Sports (Grants-in-Aid for Scientific Research to K.S.)
- Japan Society for the Promotion of Science to Young Scientists (fellowships to T.K.)
- The Global COE Program “Global Education and Research Center for Bio-Environmental Chemistry” of Osaka University (to T.K.).
- chemical shift perturbation;
- principal component analysis;
- multiple ligand binding
Chemical shift perturbations (CSPs) in NMR spectra provide useful information about the interaction of a protein with its ligands. However, in a multiple-ligand-binding system, determining quantitative parameters such as a dissociation constant (Kd) is difficult. Here, we used a method we named CS-PCA, a principal component analysis (PCA) of chemical shift (CS) data, to analyze the interaction between bovine β-lactoglobulin (βLG) and 1-anilinonaphthalene-8-sulfonate (ANS), which is a multiple-ligand-binding system. The CSP on the binding of ANS involved contributions from two distinct binding sites. PCA of the titration data successfully separated the CSP pattern into contributions from each site. Docking simulations based on the separated CSP patterns provided the structures of βLG–ANS complexes for each binding site. In addition, we determined the Kd values as 3.42 × 10−4M2 and 2.51 × 10−3M for Sites 1 and 2, respectively. In contrast, it was difficult to obtain reliable Kd values for respective sites from the isothermal titration calorimetry experiments. Two ANS molecules were found to bind at Site 1 simultaneously, suggesting that the binding occurs cooperatively with a partial unfolding of the βLG structure. On the other hand, the binding of ANS to Site 2 was a simple attachment without a significant conformational change. From the present results, CS-PCA was confirmed to provide not only the positions and the Kd values of binding sites but also information about the binding mechanism. Thus, it is anticipated to be a general method to investigate protein–ligand interactions. Proteins 2013. © 2012 Wiley Periodicals, Inc.