Molecular basis of the functional divergence of fatty acyl-AMP ligase biosynthetic enzymes of Mycobacterium tuberculosis.
Activation of fatty acids as acyl-adenylates by fatty acyl-AMP ligases (FAALs) in Mycobacterium tuberculosis is a variant of a classical theme that involves formation of acyl-CoA (coenzyme A) by fatty acyl-CoA ligases (FACLs). Here, we show that FAALs and FACLs possess similar structural fold and substrate specificity determinants, and the key difference is the absence of a unique insertion sequence in FACL13 structure. A systematic analysis shows a conserved hydrophobic anchorage of the insertion motif across several FAALs. Strikingly, mutagenesis of two phenylalanine residues, which are part of the anchorage, to alanine converts FAAL32 to FACL32. This insertion-based in silico analysis suggests the presence of FAAL homologues in several other non-mycobacterial genomes including eukaryotes. The work presented here establishes an elegant mechanism wherein an insertion sequence drives the functional divergence of FAALs from canonical FACLs.
Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad 500 007, India.
Aneesh
A
Goyal
Priyanka
P
Verma
Madhankumar
M
Anandhakrishnan
Rajesh S
RS
Gokhale
Rajan
R
Sankaranarayanan
D000214:Acyl Coenzyme A / Q000378:metabolism*; D000595:Amino Acid Sequence; D003066:Coenzyme A Ligases / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000378:metabolism; D017510:Protein Folding; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D003066:Coenzyme A Ligases