Active Site of Avian Sarcoma Virus Integrase
Home Page National Cancer Institute Macromolecular Crystallography Laboratory Retroviral Integrase Project NCI-Frederick MCL - Protein Structure Section
Structures determined by the Macromolecular Crystallography Laboratory, Protein Structure Section at the NCI-Frederick campus. Work performed in collaboration with the Skalka Laboratory in the Institute for Cancer Research, Fox Chase Cancer Center.





Nearly every image that we show of ASV IN has the invariant amino acids D64, D121, and E157 visible (in the standard single-letter code for amino acids, D is aspartic acid and E is glutamic acid). Why are we so fascinated with these three amino acids? Biochemical work by our collaborators and others has shown that mutating any of these amino acids inactivates the enzyme. Even before we solved the three-dimensional structure of ASV IN, it was speculated that these amino acids were directly involved in performing the integration reaction, perhaps by holding the essential cations that are necessary for the reaction to take place. While the rest of the protein seems to overshadow these residues, IN would be completely inactive without them.

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If you have questions or comments about the Integrase Project web site,
contact: Jerry N. Alexandratos at alexandr@ncifcrf.gov.