2-Aminopurine (hydrochloride)

2-Aminopurine is a fluorescent analog of guanosine and adenosine that is used as a site-specific probe of nucleic acid structure and dynamics. It base pairs with cytosine in a wobble configuration or with thymine in a Watson-Crick geometry. [1] In addition to its usefulness in studies of base stacking interactions, 2-aminopurine has been used as a probe for DNA base flipping by methyl transferases. [2] 2-Aminopurine exhibits an excitation/emission of 320/381 nm, respectively, when adjusted to reduce interference with DNA base absorption as well as tryptophan fluorescence. 2-Aminopurine inhibits the double-stranded RNA-dependent protein kinase, protein kinase R, whose activity mediates antiviral defense and participates in toll-like receptor signaling.[3]

Reference:
[1]. Jean, J.M., and Hall, K.B. 2-Aminopurine fluorescence quenching and lifetimes: Role of base stacking. Proc.Nat.Acad.Sci.USA 98(1), 37-41 (2001).
[2]. Holz, B., Klimasauskas, S., Serva, S., et al. 2-Aminopurine as a fluorescent probe for DNA base flipping by methyltransferases. Nucleic Acids Res. 26(4), 1076-1083 (1998).
[3]. Endoh, Y., Chung, Y.M., Clark, I.A., et al. IL-10-dependent S100A8 gene induction in monocytes/macrophages by double-stranded RNA. J. Immunol. 182(4), 2258-2268 (2009).