Abstract
The quaternary structure of δ-aminolevulinic acid dehydratase (5-aminolaevulinate hydrolyase, EC 4.2.1.24) from bovine liver was examined by analytical ultracentrifugation, polyacrylamide gel electrophoresis, and electron microscopy. The molecular weights, determined by sedimentation-velocity and sedimentation-equilibrium experiments, were 289,000 and 282,000, respectively. The molecular weight of the subunit in 6 M guanidine. HCl was 34,900 as determined by sedimentation-equilibrium and 35,000 as estimated by polyacrylamide gel electrophoresis. No evidence was obtained for the presence of a smaller polypeptide. It appears therefore that δ-aminolevulinic acid dehydratase from liver is composed of eight subunits. The molecules of the enzyme deposited in thin layers of negative stain were generally square with an edge length of 85-90 Å. On the assumption that the subunits are spherical in shape with a diameter of 44 Å and a density of 1.36 g/cm3, the molecular weight of the octamer is calculated to be 292,000. The particles appear to consist of four discrete lobes arrayed at the four corners of a square. The above conclusion that the dehydratase possesses eight subunits can be readily reconciled with the appearance of the enzyme in the electron microscope if it is postulated that the eight subunits are arranged at the corners of a cube. Therefore, it would follow that the subunits are arranged with dihedral (D4) symmetry.
Keywords: subunits, porphobilinogen, δ-aminolevulinic acid, porphyrins, electron microscopy
Full text
PDF



Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- CRAVEN G. R., STEERS E., Jr, ANFINSEN C. B. PURIFICATION, COMPOSITION, AND MOLECULAR WEIGHT OF THE BETA-GALACTOSIDASE OF ESCHERICHIA COLI K12. J Biol Chem. 1965 Jun;240:2468–2477. [PubMed] [Google Scholar]
- Cheh A., Neilands J. B. Zinc, an essential metal ion for beef liver delta-aminolevulinate dehydratase. Biochem Biophys Res Commun. 1973 Dec 19;55(4):1060–1063. doi: 10.1016/s0006-291x(73)80002-6. [DOI] [PubMed] [Google Scholar]
- Darnall D. W., Klotz I. M. Protein subunits: a table (revised edition). Arch Biochem Biophys. 1972 Mar;149(1):1–14. doi: 10.1016/0003-9861(72)90293-7. [DOI] [PubMed] [Google Scholar]
- Doyle D. Subunit structure of -aminolevulinate dehydratase from mouse liver. J Biol Chem. 1971 Aug 25;246(16):4965–4972. [PubMed] [Google Scholar]
- Gurba P. E., Sennett R. E., Kobes R. D. Studies on the mechanism of action of -aminolevulinate dehydratase from bovine and rat liver. Arch Biochem Biophys. 1972 May;150(1):130–136. doi: 10.1016/0003-9861(72)90019-7. [DOI] [PubMed] [Google Scholar]
- Nandi D. L., Shemin D. Delta-aminolevulinic acid dehydratase of Rhodopseudomonas spheroides. 3. Mechanism of porphobilinogen synthesis. J Biol Chem. 1968 Mar 25;243(6):1236–1242. [PubMed] [Google Scholar]
- Shapiro A. L., Viñuela E., Maizel J. V., Jr Molecular weight estimation of polypeptide chains by electrophoresis in SDS-polyacrylamide gels. Biochem Biophys Res Commun. 1967 Sep 7;28(5):815–820. doi: 10.1016/0006-291x(67)90391-9. [DOI] [PubMed] [Google Scholar]
- Van Heyningen S., Shemin D. Quaternary structure of -aminolevulinate dehydratase from Rhodopseudomonas spheroides. Biochemistry. 1971 Dec 7;10(25):4676–4682. doi: 10.1021/bi00801a013. [DOI] [PubMed] [Google Scholar]
- Weber K., Osborn M. The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J Biol Chem. 1969 Aug 25;244(16):4406–4412. [PubMed] [Google Scholar]
- Williams R. C., Fisher H. W. Electron microscopy of tobacco mosaic virus under conditions of minimal beam exposure. J Mol Biol. 1970 Aug 28;52(1):121–123. doi: 10.1016/0022-2836(70)90181-6. [DOI] [PubMed] [Google Scholar]
- Wilson E. L., Burger P. E., Dowdle E. B. Beef-liver 5-aminolevulinic acid dehydratase. Purification and properties. Eur J Biochem. 1972 Sep 25;29(3):563–571. doi: 10.1111/j.1432-1033.1972.tb02022.x. [DOI] [PubMed] [Google Scholar]
- YPHANTIS D. A. EQUILIBRIUM ULTRACENTRIFUGATION OF DILUTE SOLUTIONS. Biochemistry. 1964 Mar;3:297–317. doi: 10.1021/bi00891a003. [DOI] [PubMed] [Google Scholar]




