5-Bromo-deoxycytosine (Bromo-dC, Figure 1) is a halogenated nucleotide, commonly used in X-ray crystallography to facilitate the determination of DNA structure. Additionally, bromo nucleotides are photo-labile and therefore suitable for UV-crosslinking experiments to study protein-DNA complexes. 5-Br-dU was also used to create photo-aptamers able to crosslink with their target.
Figure 1. Structure of 5-Bromo-deoxycytosine (R = sequence).
metabion offers the Bromo-dC modification in its DNA and RNA portfolio: