High-resolution crystal structure of deoxy hemoglobin complexed with a potent allosteric effector.
Safo, M.K., Moure, C.M., Burnett, J.C., Joshi, G.S., Abraham, D.J.(2001) Protein Sci 10: 951-957
- PubMed: 11316875 
- DOI: https://doi.org/10.1110/ps.50601
- Primary Citation of Related Structures:  
1G9V - PubMed Abstract: 
The crystal structure of human deoxy hemoglobin (Hb) complexed with a potent allosteric effector (2-[4-[[(3,5-dimethylanilino)carbonyl]methyl]phenoxy]-2-methylpropionic acid) = RSR-13) is reported at 1.85 A resolution. Analysis of the hemoglobin:effector complex indicates that two of these molecules bind to the central water cavity of deoxy Hb in a symmetrical fashion, and that each constrains the protein by engaging in hydrogen bonding and hydrophobic interactions with three of its four subunits. Interestingly, we also find that water-mediated interactions between the bound effectors and the protein make significant contributions to the overall binding. Physiologically, the interaction of RSR-13 with Hb results in increased oxygen delivery to peripheral tissues. Thus, this compound has potential therapeutic application in the treatment of hypoxia, ischemia, and trauma-related blood loss. Currently, RSR-13 is in phase III clinical trials as a radiosensitizing agent in the treatment of brain tumors. A detailed structural analysis of this compound complexed with deoxy Hb has important implications for the rational design of future analogs.
Organizational Affiliation: 
Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23298-0540, USA.