List of Figures with
captions
Figure 1 A) Structure of FadL: The α-helices of the
extracellular region forming the opening of a hydrophobic groove are
shown in orange. Inside the protein, several residues that can interact
from the binding pocket are shown in red. The hatch domain of the
intracellular region is shown in blue. Finally, one of the β-strands
(strand 3 or S3), presents a bend or a kink, shown in green, that leads
to the formation of an opening in the intramembrane surface of the
protein. B) Transport mechanism of FadL: Schematic
representation of the transport mechanism of FadL proposed by Lepore et
al., 2011. The yellow box represents the bilipid layer and the red
hexagons the lipopolysaccharide layer.
Figure 2 Bacterial fatty acid import systems: A) In certain
Gram-negative bacteria a membrane-associated acyl-CoA synthetase imports
the fatty acids to the cytosol in the form of acyl-CoA, a process known
as vectorial acylation. B) In Gram-positive bacteria, single
proteins have been identified in organisms such as R. jostii andM. tuberculosis which may be able to import free fatty acids into
the cells, which will be later activated for their metabolization.C) In M. tuberculosis, the multiprotein complex Mce has
been identified. The figure shows a hypothetical model adapted from
Nazarova et al., 2019.
Figure 3 Structure of the AcrAB-TolC complex: The multiprotein
complex AcrAB-TolC spans from the inner to the outer membrane.
Figure 4 Structure of Fat1: Fat1 presents two transmembrane
domains and two domains which are partially integrated in the membrane.
ATP/AMP binding domains are found near the two latter domains. A VLACS
domain is found further in the C-terminal region. Finally, the soluble
Faa1 has been observed to interact with the C-terminus of this protein
to activate the imported fatty acids.
Figure 5 Intracellular trafficking of fatty acids in yeast
cells: Simplified fatty acid transport routes in S. cerevisiaebased on current knowledge. Both plasma membrane transport processes and
intracellular trafficking routes are showed.
Figure 6 Intracellular trafficking of fatty acids in microalgae
cells: Fatty acid intracellular trafficking routes in C.
reinhardtii. No transport system has been described for the outer
plastid membrane and for the export of free fatty acids to the
extracellular media.