2,6-Diaminopurine is a nucleotide analogue that is synthesized from guanosine. It inhibits the enzyme ribonucleotide reductase and blocks the synthesis of DNA precursors, which are necessary for viral replication. 2,6-Diaminopurine has been shown to inhibit hiv infection in tissue culture and animal models by decreasing the levels of nucleotides in cells. This drug can be used as an anti-viral agent against HIV and other retroviruses. 2,6-Diaminopurine has also been shown to be effective against murine sarcoma virus. The compound binds to the enzyme ribonucleotide reductase, which is important for DNA synthesis, and prevents its activity by mimicking adenosine triphosphate (ATP). The binding of 2,6-diaminopurine to ATP results in a coordination geometry that causes a long hydrogen bond with one oxygen