Abstract
Sterol carrier protein 2 (SCP2) has been investigated by nearly native electrospray ionisation mass spectrometry in the presence of long chain fatty acyl CoAs (LCFA-CoAs) and carnitine derivatives of equivalent fatty acid chain length (LCFA-carnitines). Four SCP2 constructs were compared to examine the influence of the N-terminal presequence and the C-terminal peroxisomal targeting signal on ligand binding. Removal of N- or C-terminal residues did not influence ligand binding. The observation that LCFA-CoAs are high affinity ligands for SCP2 was confirmed, while LCFA-carnitines were demonstrated for the first time not to interact with SCP2. LCFA-CoAs formed non-covalent complexes with SCP2 of 2:1 and 1:1 stoichiometry, which could be dissociated by elevating the energy of the ions upon entrance to the mass spectrometer. A fluorescence-competition assay using Nile Red butyric acid confirmed the mass spectrometric observations in solution. The physiological significance of the lack of LCFA-carnitine binding by SCP2 is discussed.
Original language | English (US) |
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Pages (from-to) | 50-58 |
Number of pages | 9 |
Journal | Archives of Biochemistry and Biophysics |
Volume | 461 |
Issue number | 1 |
DOIs | |
State | Published - May 1 2007 |
Externally published | Yes |
Keywords
- Electrospray mass spectrometry
- Fatty acyl CoA
- Fatty acyl carnitine
- Nile Red butyric acid
- Non-specific lipid transfer protein
- Sterol carrier protein 2 (SCP2)
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology