A hybrid of the transhydrogenases from Rhodospirillum rubrum and Mycobacterium tuberculosis catalyses rapid hydride transfer but not the complete, proton-translocating reaction

Biochimica Et Biophysica Acta
Rosalind WilsonJ Baz Jackson

Abstract

All transhydrogenases appear to have three components: dI, which binds NAD(H), and dIII, which binds NADP(H), protrude from the membrane, and dII spans the membrane. However, the polypeptide composition of the enzymes varies amongst species. The transhydrogenases of Mycobacterium tuberculosis and of Rhodospirillum rubrum have three polypeptides. Sequence analysis indicates that an ancestral three-polypeptide enzyme evolved into transhydrogenases with either two polypeptides (such as the Escherichia coli enzyme) or one polypeptide (such as the mitochondrial enzyme). The fusion steps in each case probably led to the development of an additional transmembrane helix. A hybrid transhydrogenase was constructed from the dI component of the M. tuberculosis enzyme and the dII and dIII components of the R. rubrum enzyme. The hybrid catalyses cyclic transhydrogenation but not the proton-translocating, reverse reaction. This shows that nucleotide-binding/release at the NAD(H) site, and hydride transfer, are fully functional but that events associated with NADP(H) binding/release are compromised. It is concluded that sequence mismatch in the hybrid prevents a conformational change between dI and dIII which is essential for the step accompan...Continue Reading

References

May 5, 1982·Journal of Molecular Biology·J Kyte, R F Doolittle
Jul 3, 1995·Proceedings of the National Academy of Sciences of the United States of America·C G Clark, A J Roger
Mar 1, 1996·FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology·Y Hatefi, M Yamaguchi
Jun 26, 1999·Science·W F Doolittle
Jun 26, 1999·The Journal of Biological Chemistry·J Meuller, J Rydström
Dec 10, 1999·Microbial & Comparative Genomics·W K StudleyM H Saier
Jan 19, 2000·Trends in Genetics : TIG·B SnelM Huynen
Jul 19, 2000·Proceedings of the National Academy of Sciences of the United States of America·C R Woese
Nov 23, 2000·Current Opinion in Genetics & Development·J A Eisen
May 11, 2002·The Journal of Biological Chemistry·Chris J WestonJ Baz Jackson
Oct 16, 2002·Biochemistry·G Sridhar PrasadC David Stout
Jun 6, 2003·FEBS Letters·J Baz Jackson
Nov 1, 1959·Clinica Chimica Acta; International Journal of Clinical Chemistry·P G SCHEURLEN
Jan 27, 2005·Journal of Molecular Biology·Vidyasankar SundaresanC David Stout

❮ Previous
Next ❯

Related Concepts

Related Feeds

Amoebiasis

Amoebiasis, infection by the protozoan parasite Entamoeba histolytica, remains a global health problem, despite the availability of effective treatment. Here is the latest research.