Biochemistry Program (M103KV010005-06K2201-00610); and the BioImag- ing Research Center at the Gwangju Institute of Science and Technology and Basic Research Projects in High-tech Industrial Technology funded by the Gwangju Institute of Science and Technology in 2011. Notes The authors declare no competing financial interest. We are grateful to Dr. Chul-Seung Park for critical reading of the manuscript. ACKNOWLEDGMENTS ABBREVIATIONS ■ ■ ■ CD, circular dichroism; DSS, 4,4-dimethyl-4-silapentane-1- sulfonic acid; DQF-COSY, double-quantum-filtered correlation spectroscopy; E-COSY, exclusive COSY; HSQC, heteronuclear single-quantum coherence; MALDI-TOF MS, matrix-assisted laser desorption ionization time-of-flight mass spectrometry; NMR, nuclear magnetic resonance; NOE, nuclear Overhauser effect; NOESY, nuclear Overhauser effect spectroscopy; PDB, Protein Data Bank; RP-HPLC, reverse phase high-performance liquid chromatography; TOCSY, total correlated spectroscopy. 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