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Journal of Spectroscopy
Volume 2013, Article ID 314345, 11 pages
http://dx.doi.org/10.1155/2013/314345
Research Article

Site-Directed Mutagenesis of Myoglobin for Studies of Their Interaction with Iron(III) by Multi-Spectroscopic Techniques

1Faculty of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian City 116024, China
2Liaoning Key Laboratory of Bioorganic Chemistry, Dalian University, Dalian City 116622, China

Received 25 April 2012; Revised 11 July 2012; Accepted 12 July 2012

Academic Editor: Daniel Oscar Cicero

Copyright © 2013 Qian Tang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In order to investigate how the amino acids on the surface of myoglobin molecule influence myoglobin's structure and function, a variety of spectroscopy techniques were applied in the study of the interaction between Fe(III) and myoglobin (wild type and its mutants, D44K, D60K, and K56D). The results demonstrate that Fe(III) can quench the fluorescence of wild type and mutants of myoglobin, and the quenching mechanisms are static quenching. It is found that the binding distance between Fe(III) and myoglobin mutants gets smaller, the binding capacity increases by the values of binding constant and the bimolecular quenching constant as well as the binding distance. Those data also indicate that the metal ion Fe(III) can interact strongly with myoglobin mutants. The three-dimensional conformation change after surface amino acids are replaced is detected by the UV absorption spectroscopy and fluorescence spectroscopy, which make mutants become more dynamic and change its function and interaction with Fe(III) strongly.