Scott AI, Clemens KR, Stolowich NJ, Santander PJ, Gonzalez MD, Roessner CA. Reconstitution of apo-porphobilinogen deaminase: structural changes induced by cofactor binding.
FEBS Lett 1989;
242:319-24. [PMID:
2644132 DOI:
10.1016/0014-5793(89)80493-4]
[Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Expression of porphobilinogen deaminase in a hemB- strain of E. coli has permitted the isolation of the apoenzyme, i.e. deaminase lacking the porphobilinogen-derived dipyrromethane cofactor. Incubation of purified apoenzyme with porphobilinogen resulted in reconstitution of the covalently attached dipyrromethane cofactor, indicating no additional cofactors or enzymes are required for biosynthesis of holoenzyme. Electrophoretic and 13C-NMR spectroscopic analyses demonstrate that the apoenzyme exists in a conformationally unstable form which is converted to a highly stable tertiary structure on covalent attachment of the dipyrromethane cofactor.
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