pfaBproducts determine the molecular species produced in bacterial polyunsaturated fatty acid biosynthesis

Abstract

When pDHA4, a vector carrying all five pfaA-pfaE genes responsible for docosahexaenoic acid (DHA; 22:6) biosynthesis in Moritella marina MP-1, was coexpressed in Escherichia coli with the individual pfaA-pfaD genes for eicosapentaenoic acid (EPA; 20:5) biosynthesis from Shewanella pneumatophori SCRC-2738, both polyunsaturated fatty acids were synthesized only in the recombinant carrying pfaB for EPA synthesis. Escherichia coli coexpressing a deleted construct comprising pfaA, pfaC, pfaD and pfaE for EPA and pfaB for DHA produced EPA and DHA. Both EPA and DHA were detected in bacteria that inherently contained pfa genes for DHA. These results suggest that PfaB is the key enzyme determining the final product in EPA or DHA biosynthesis.

Possible Biosynthetic Pathways for all cis‐3,6,9,12,15,19,22,25,28‐Hentriacontanonaene in Bacteria

“…The same compound (C31:9) was detected in marine and nonmarine, and psychrophilc and mesophilic bacteria, which contained EPA and/or DHA (Table 4). Based on our present results, previous studies on the bacterial distribution of PUFAs and pfa genes [3], and data on the predicted biosynthetic pathway of PUFAs in the polyketide synthesis mode [37,39,40], we will discuss the biosynthetic routes of C31:9.…”

“…To investigate effects of temperature on growth and production of C31:9, strain osh08 was cultivated at 0, 4,15,20,25,30,37,40, and 43 °C.…”

FabQ, a Dual-Function Dehydratase/Isomerase, Circumvents the Last Step of the Classical Fatty Acid Synthesis Cycle

“…The enoyl-ACP reductase-independent elongation pathway we postulate (Figure 7) has parallels in the bacterial synthesis of polyunsaturated fatty acids by certain type I polyketide synthases called polyunsaturated fatty acid synthases (Jiang et al, 2008; Metz et al, 2001; Orikasa et al, 2009). These poly-functional protein systems all contain dehydratase domains that strongly resemble E. coli FabA and some also have FabZ-like domains (Orikasa et al, 2009).…”

Effects of Aerobic Growth on the Fatty Acid and Hydrocarbon Compositions of <i>Geobacter bemidjiensis</i> Bem^T

“…Fatty acids and HCs were identified by comparing retention times with those of authentic standards or fatty acids and HCs derived from the reference strains. For this purpose, we used a gas chromatograph GC Model GC-353B, GL Sciences, Tokyo, Japan equipped with a polar capillary column type TC-70, 30-m long, 0.25-mm I.D., 0.25-µm film thickness; GL Sciences Inc., Tokyo and a flame ionization detector with nitrogen as the carrier gas, as described previously 28 . The identities of these components were determined by GC-mass spectrometry GC-MS using a Varian system Model CP-3800 GC and a Saturn 2200 ion trap mass spectrometer; Varian Technologies Japan, Inc., Tokyo equipped with the same column 28 .…”