1H7D: Solution structure of the 49 aa presequence of 5-ALAS

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.
PDB ID: 1H7DDownload
MMDB ID: 17730
PDB Deposition Date: 2001/7/5
Updated in MMDB: 2001/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 1H7D: monomeric; determined by author
Molecular Components in 1H7D
Label Count Molecule
Protein (1 molecule)
Aminolevulinic Acid Synthase 2, Erythroid
Molecule annotation
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Citing MMDB