If you visit the nursery in a hospital, you may see babies under fluorescent lamps - these babies are undergoing treatment for jaundice, a condition caused by the abnormally high level of bilirubins in the bloodstream. Bilirubins can be neurotoxic, and accumulation of this compound in an infant's brain could cause irreversible damage.
Bilirubins are the breakdown product of heme - the oxygen-binding factor of hemoglobin - released from red blood cells that have been destroyed. However, they are not waste products that are completely bad for us. In fact, bilirubins are potent antioxidants made by the human body. Thus, the molecular details of how they are converted from heme are important for understanding how bilirubin production is regulated to benefit rather than harm us.
Heme is converted into bilirubins in two steps: it is first cleaved to produce unstable intermediates, biliverdins; these intermediates are then further processed to bilirubins by enzymes called biliverdin reductases. To understand how these enzymes convert biliverdins into bilirubins, Miquel Coll of the Institut de Biologia Molecular de Barcelona, Spain, and his colleagues at Trinity College, Ireland, as well as Akihiro Kikuchi and coworkers at the RIKEN Harima Institute, Japan, have determined the crystal structures of two different biliverdin reductases (Nature Structural Biology, Vol. 8, No. 3, 01 Mar 2001). These structures provide a wealth of information about the molecular details of bilirubin production.
Antony McDonagh at the University of California San Francisco discusses these findings in an associated News and Views.
Contact information: Dr. Akihiro Kikuchi
RIKEN Harima Institute/SPring-8
Sayo, Hyogo 679-5148
Telephone: +81 791 58 2817
Fax: +81 791 58 2818
Professor Miquel Coll
Institut de Biologia Molecular de Barcelona
Consejo Superior de Investigaciones Cientificas
Jordi Girona, 18-26
Telephone: +34 3 400 6149
Fax: +34 3 204 5904
Professor Antony McDonagh
University of California San Francisco
Division of Gastroenterology
Box 0538, Room S-357
San Francisco, California 94143-0538
Telephone: +1 415-476-6425
Fax: +1 415-476-0659
(C) Nature Structural Biology press release.
Message posted by: Trevor M. D'Souza