The structure of bilirubin
- 23 June 1978
- journal article
- research article
- Published by The Royal Society in Proceedings of the Royal Society of London. B. Biological Sciences
- Vol. 202 (1147) , 249-268
- https://doi.org/10.1098/rspb.1978.0066
Abstract
Crystals of bilirubin are triclinic, space group P1̄ with cell dimensions a = 19.439, b = 11.707, c = 15.500 Å, †, α = 97.19, β =100.22, γ = 118.20°, Z = 4. The structure was solved by direct methods incorporating information derived from reflexion quartets and by using a set of diffractometer data containing 1408 reflexions with F obs ≥ 3σ( F obs ). The structure was refined with bond-length constraints to a final R of 0.125 by using a set of microdensitometer-measured photographic data containing 1323 unique observed reflexions. Both data sets were collected from a matured crystal whose diffraction pattern had improved considerably during a period of several weeks. Bilirubin is shown to have the Z configuration at both the C5 and C15 bridges. The two independent molecules of bilirubin in the crystal structure have very similar ‘ridge tile’ conformations: rings (A + B) and rings (C + D) form two good planes with an interplanar angle of approximately 97° and the molecule is stabilized by six intramolecular hydrogen bonds. There is no evidence for any intermolecular hydrogen bonding. Observed bond lengths suggest that bilirubin can be regarded as a 2,2' - dipyrrolylmethane with conjugating substituents at the α positions. When freshly prepared, most crystals of bilirubin have reflexions hkl ( h odd) diffuse: this observation is discussed in terms of the molecular conformation of bilirubin and the particular packing arrangement which these molecules adopt in the crystal structure.Keywords
This publication has 16 references indexed in Scilit:
- Free-energy barrier of conformational inversion in bilirubinJournal of the Chemical Society, Chemical Communications, 1976
- The configurations of the isomeric 3,4-dimethyl-5-(1h)-2,2′-pyrromethenonesTetrahedron Letters, 1975
- Appendix: Structure and conformation of bilirubin. Opposing views that invoke tautomeric equilibria, hydrogen bonding and a betaine may be reconciled by a single resonance hybridBiochemical Journal, 1973
- INFLUENCE OF PHOTOTHERAPY ON UNCONJUGATED BILIRUBIN IN DUODENAL BILE OF NEWBORN INFANTS WITH HYPERBILIRUBINEMIA A Preliminary StudyActa Paediatrica, 1972
- Crystallographic studies in the pyrrole series. Part II. Crystal and molecular structure of 5,5′-diethoxycarbonyl-3,3′,4,4′-tetraethyldipyrrol-2-ylmethaneJournal of the Chemical Society, Perkin Transactions 2, 1972
- Crystallographic studies in the pyrrole series. Part I. Crystal and molecular structure of ethyl 4-acetyl-3-ethyl-5-methylpyrrole-2-carboxylateJournal of the Chemical Society, Perkin Transactions 2, 1972
- Photocatabolism of labeled bilirubin in the congenitally jaundiced (Gunn) ratJournal of Clinical Investigation, 1971
- Intramolecular Hydrogen Bonding in Bilirubin.Acta Chemica Scandinavica, 1967
- ON THE ORIGIN OF THE OPTICAL ACTIVITY IN THE UROBILINSProceedings of the National Academy of Sciences, 1964
- Structure of BilirubinNature, 1963