The YfiD protein contributes to the pyruvate formate-lyase flux in an Escherichia coli arcA mutant strain
✍ Scribed by Jiangfeng Zhu; Sagit Shalel-Levanon; George Bennett; Ka-Yiu San
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 203 KB
- Volume
- 97
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Abstract
The product of __yfi__D gene is similar to pyruvate formate‐lyase (PFL) activase and it has been reported to activate PFL by replacing the glycyl radical domain. To quantitate the effect of YfiD on the cell metabolism in microaerobic cultures, glucose‐limited chemostat cultures were conducted with __Escherichia coli yfi__D mutant and __yfi__D__arc__A mutant strains. The microaerobic condition was controlled by purging the culture media with 2.5% O~2~ in N~2~. The intracellular metabolic flux distributions in these cultures were estimated based on C‐13 labeling experiments. By comparing with the flux distributions in wild‐type E. coli and the __arc__A mutant, it was shown that YfiD contributes to about 18% of the PFL flux in the __arc__A mutant, but it did not contribute to the PFL flux in wild‐type E. coli. It was also shown that the cell used both PFL and pyruvate dehydrogenase (PDH) to supplement the acetyl‐coenzyme A (AcCoA) pool under microaerobic conditions. The flux through PDH was about 22–30% of the total flux toward AcCoA in the wild‐type, the __yfi__D mutant and __yfi__D__arc__A mutant strains. Relatively higher lactate production was seen in the __yfi__D__arc__A mutant than the other strains, which was due to the lower total flux through PFL and PDH toward AcCoA in this strain. Biotechnol. Bioeng. 2007;97:138–143. © 2006 Wiley Periodicals, Inc.