Unsaturated Lipid Assimilation by Mycobacteria Requires Auxiliary cis-trans Enoyl CoA Isomerase

Abstract

Mycobacterium tuberculosis (Mtb) can survive in hypoxic necrotic tissue by assimilating energy from host-derived fatty acids. While the expanded repertoire of β-oxidation auxiliary enzymes is considered crucial for Mtb adaptability, delineating their functional relevance has been challenging. Here, we show that the Mtb fatty acid degradation (FadAB) complex cannot selectively break down cis fatty acyl substrates. We demonstrate that the stereoselective binding of fatty acyl substrates in the Mtb FadB pocket is due to the steric hindrance from Phe287 residue. By developing a functional screen, we classify the family of Mtb Ech proteins as monofunctional or bifunctional enzymes, three of which complement the FadAB complex to degrade cis fatty acids. Crystal structure determination of two cis-trans enoyl coenzyme A (CoA) isomerases reveals distinct placement of active-site residue in Ech enzymes. Our studies thus reveal versatility of Mtb lipid-remodeling enzymes and identify an essential role of stand-alone cis-trans enoyl CoA isomerases in mycobacterial biology.

Complementary transcriptome and proteome profiling in the mature seeds of Camellia oleifera from Hainan Island

“…The correlative research shows that enoyl-CoA hydratase (ECH) catalyzes the second step in the physiological β-oxidation pathway of fatty acid metabolism [67,68]. It is worth noting that the energy provided from fatty acids to organisms could be blocked without this enzyme, and the absence of this protein would lead to an increase in levels of unsaturated fatty acids, especially oleic acid and linoleic acid [69]. Aldehyde dehydrogenase (ALDH) is used as a reliable marker to separate stem cells and has been stated to play an important role in cell proliferation and protection [70,71].…”

Differential determinants of virulence in twoMycobacterium tuberculosisColombian clinical isolates of the LAM09 family

“…It has been previously shown that fadD6 function as a fatty acid transporter, and its protein level was higher in Mtb H37Rv bacilli in a dormant state than in Mtb in the exponential growth phase [41]. The family of Ech proteins of Mtb is involved in the degradation of cis fatty acids [42]. EchA2 is a monofunctional enoyl CoA isomerase [41] may be involved in unsaturated fatty acid metabolism and essential for Mtb survival in lipid-rich environments [10].…”

Identification of FadAB Complexes Involved in Fatty Acid β-Oxidation in Streptomyces coelicolor and Construction of a Triacylglycerol Overproducing strain

“…Altogether, these results indicate that SCOfadAB gene products can display catalytic activities attributable to E. coli FadBA complex when expressed in the E. coli Δ fadBA mutant, namely: enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase (Yang et al, 1988 ; Srivastava et al, 2015 ). Furthermore, the complementation studies also suggest that the other β-oxidation enzymes (FadL, FadD, and FadE) present in E. coli can functionally interact with SCOfadAB gene products for exogenous FA assimilation.…”

“…Neighbor-joining phylogenetic trees based on amino acid sequence of FadB enzymes from different organisms, group SCO6732 and SCO6789 together with FadB from the actinomycetes Mycobacterium tuberculosis (64 and 63% identity, respectively; Srivastava et al, 2015 ) and Rhodococcus equi (64 and 61% identity, respectively; Kelly et al, 2002 ; Figure 1C ). In contrast, SCO6026 is placed near to FadB sequences from Gram (−) bacteria: E .…”

“…These authors propose a model in which FadBA complex degrades long-chain FA and releases short- and medium-chain length intermediates that are substrates for the YfcYX complex (Campbell et al, 2003 ). More restricted substrate specificity was reported for M. tuberculosis FadB, which needs the action of a trans-acting enoyl-CoA isomerase in order to completely degrade cis-unsaturated FA (Srivastava et al, 2015 ). In the case of S. coelicolor FadAB complexes, low efficiency or narrow substrate specificity range of the complexes in the E. coli context might account for the lower growth rates exhibited by strains complemented with SCOfadAB_2 and SCOfadAB_3 when oleic acid is the sole carbon source.…”