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B6db references: 11566198

type Journal Article
authors Goodfellow, B. J.; Dias, J. S.; Ferreira, G. C.; Henklein, P.; Wray, V.; Macedo, A. L.
title The solution structure and heme binding of the presequence of murine 5- aminolevulinate synthase
journal FEBS Lett
sel selected
ui 11566198
year (2001)
volume 505
number 2
pages 325-31
keywords 5-Aminolevulinate Synthetase/*chemistry/*metabolism
abstract The mitochondrial import of 5-aminolevulinate synthase (ALAS), the first enzyme of the mammalian heme biosynthetic pathway, requires the N- terminal presequence. The 49 amino acid presequence transit peptide (psALAS) for murine erythroid ALAS was chemically synthesized, and circular dichroism and (1)H nuclear magnetic resonance (NMR) spectroscopies used to determine structural elements in trifluoroethanol/H(2)O solutions and micellar environments. A well defined amphipathic alpha-helix, spanning L22 to F33, was present in psALAS in 50% trifluoroethanol. Further, a short alpha-helix, defined by A5-L8, was also apparent in the 26 amino acid N-terminus peptide, when its structure was determined in sodium dodecyl sulfate. Heme inhibition of ALAS mitochondrial import has been reported to be mediated through cysteine residues in presequence heme regulatory motifs (HRMs). A UV/visible and (1)H NMR study of hemin and psALAS indicated that a heme-peptide interaction occurs and demonstrates, for the first time, that heme interacts with the HRMs of psALAS.
last changed 2009/01/12 19:12

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