Exhibits a pH-dependent oligomerization state: at pH 7, the dominant species is a dimer, where each monomer is a two-CBS domain protein, and at pH 4.5-4.8, the dominant species is a tetramer, with an oblong shape (PubMed:18607087, PubMed:19267448). At pH 2.5, there is formation of intermolecular hydrogen bonds, suggesting the presence of high-molecular weight species (PubMed:19267448). The physiological dimeric species is thermal and chemically very stable (PubMed:19267448). The CBS domains bind adenosine derivatives (AMP, ATP, NADP and SAM) (PubMed:20959390). The CBS domains can also bind calf-thymus DNA and E-boxes recognized by transcription factors (PubMed:20934423). Binding of the nucleotides induces protein conformational changes (PubMed:20934423, PubMed:20959390).