Substitution of murine ferrochelatase glutamate-287 with glutamine or alanine leads to porphyrin substrate-bound variants

The Biochemical Journal
R FrancoG C Ferreira

Abstract

Ferrochelatase (EC 4.99.1.1) is the terminal enzyme of the haem biosynthetic pathway and catalyses iron chelation into the protoporphyrin IX ring. Glutamate-287 (E287) of murine mature ferrochelatase is a conserved residue in all known sequences of ferrochelatase, is present at the active site of the enzyme, as inferred from the Bacillus subtilis ferrochelatase three-dimensional structure, and is critical for enzyme activity. Substitution of E287 with either glutamine (Q) or alanine (A) yielded variants with lower enzymic activity than that of the wild-type ferrochelatase and with different absorption spectra from the wild-type enzyme. In contrast to the wild-type enzyme, the absorption spectra of the variants indicate that these enzymes, as purified, contain protoporphyrin IX. Identification and quantification of the porphyrin bound to the E287-directed variants indicate that approx. 80% of the total porphyrin corresponds to protoporphyrin IX. Significantly, rapid stopped-flow experiments of the E287A and E287Q variants demonstrate that reaction with Zn(2+) results in the formation of bound Zn-protoporphyrin IX, indicating that the endogenously bound protoporphyrin IX can be used as a substrate. Taken together, these findings ...Continue Reading

References

Dec 1, 1977·Proceedings of the National Academy of Sciences of the United States of America·F SangerA R Coulson
Nov 3, 1995·The Journal of Biological Chemistry·R FrancoG C Ferreira
Jan 18, 1994·Biochemistry·H A DaileyM K Johnson
May 18, 1999·Acta Crystallographica. Section D, Biological Crystallography·K F WangH A Dailey
Mar 8, 2000·Biochemistry·R FrancoJ A Shelnutt
Mar 8, 2000·Journal of Molecular Biology·D LecerofS Al-Karadaghi
Dec 1, 1950·Biometrika·J DURBIN, G S WATSON

❮ Previous
Next ❯

Citations

Sep 22, 2009·The Journal of Biological Chemistry·Ruth E DavidsonJames D Reid
Jun 5, 2008·Biochemistry and Cell Biology = Biochimie Et Biologie Cellulaire·Shukui GuoMichèle C Loewen
Jun 23, 2009·Journal of Biological Inorganic Chemistry : JBIC : a Publication of the Society of Biological Inorganic Chemistry·Borys SzefczykJosé A N F Gomes
Sep 22, 2007·Journal of Molecular Biology·Amy E MedlockWilliam N Lanzilotta
May 23, 2003·Journal of Biological Inorganic Chemistry : JBIC : a Publication of the Society of Biological Inorganic Chemistry·David LecerofSalam Al-Karadaghi
Feb 26, 2004·The Journal of Biological Chemistry·Zhen Shi, Gloria C Ferreira

❮ Previous
Next ❯

Related Concepts

Related Feeds

Biosynthetic Transformations

Biosyntheic transformtions are multi-step, enzyme-catalyzed processes where substrates are converted into more complex products in living organisms. Simple compounds are modified, converted into other compounds, or joined together to form macromolecules. Discover the latest research on biosynthetic transformations here.