a cytidine(6-4)cytidine in DNA <=> a cytidine dimer in DNA + H(+)
a cytidine(6-4)cytidine in dna <=> a cytidine dimer in dna + h(+)
a cytidine(6-4)cytidine in DNA <=> a cytidine dimer in DNA + H(+)
a cytidine(6-4)cytidine in dna <=> a cytidine dimer in dna + h(+)