The Dimerization State of the Mammalian High Mobility Group Protein AT-Hook 2 (HMGA2)

• Published in: PloS one Vol. 10; no. 6; p. e0130478
• Main Authors: Frost, Lorraine, Baez, Maria A M, Harrilal, Christopher, Garabedian, Alyssa, Fernandez-Lima, Francisco, Leng, Fenfei
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26-06-2015; Public Library of Science (PLoS)
• Subjects: Analysis; Animals; Biochemistry; Buffer solutions; C-Terminus; Cancer; Carbodiimide; Cell growth; Chemistry; Chromosomal proteins; Circular Dichroism; Crosslinking; Deoxyribonucleic acid; Dichroism; Dimerization; DNA; Electrostatic properties; Energy transfer; Ethyldimethylaminopropyl Carbodiimide - chemistry; Experiments; Fluorescence; Fluorescence Resonance Energy Transfer; Genetic transformation; High mobility group proteins; HMGA2 Protein - chemistry; Hooks; Hydrodynamics; Mammals; Mass Spectrometry; Mass spectroscopy; Mice; Mobility; Mutagenesis; Protein structure; Proteins; Tertiary structure; Transformation; Tumorigenesis; Tumors; Ultracentrifugation; Florida; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0130478

The mammalian high mobility group protein AT-hook 2 (HMGA2) is a chromosomal architectural transcription factor involved in cell transformation and oncogenesis. It consists of three positively charged "AT-hooks" and a negatively charged C-terminus. Sequence analyses, circular dichroism experiments, and gel-filtration studies showed that HMGA2, in the native state, does not have a defined secondary or tertiary structure. Surprisingly, using combined approaches of 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) chemical cross-linking, analytical ultracentrifugation, fluorescence resonance energy transfer (FRET), and mass spectrometry, we discovered that HMGA2 is capable of self-associating into homodimers in aqueous buffer solution. Our results showed that electrostatic interactions between the positively charged "AT-hooks" and the negatively charged C-terminus greatly contribute to the homodimer formation.