The Study Of Acetoin Metabolism In Bacteria

In this paper, the sequences of the unknown protein AcoX associated with acetoin metabolism were aligned using the NCBI database. The characters and function of AcoX were predicted. The acoX gene was cloned and expressed using the genome of P. putida KT2440 as the template. AcoX was then purified and analyzed using circular dichroism spectroscopy.AcoX was noted as NADK in the NCBI database. There are two highly conserved sequences: the GGDG motif and the Gly-rich motif in the amino acid sequences of the NADK family. But there were only the GGDG motif and other unique conserved motifs in AcoX, but no Gly-rich motif. So we predicted that AcoX was not NADK. The prediction was proved to be true by further experiments.The acoX gene was cloned and expressed using the P. putida KT2440 genome as the template. Then AcoX was purified with the nickel column. Circular dichroism spectroscopy was used to determine the secondary structure of AcoX. The result showed that its secondary structure was a mixture ofαhelixs andβsheets.The acoA gene was cloned and expressed using the genome of Bacillus subtilis 168 as the template. AcoA was purified with the nickel column and then tested its E1 activity. But no activity was detected, indicating that E1 is coded by both the E1αsubunit and E1βsubunit and E1βsubunit is indispensable in the correct function of E1.Gas chromatography was used to detect the volatile products in the glucose fermentation experiment. Acetoin, and then a little 2,3-butanediol, were detected. The relationship between the growth of bacterium and products accumulation was studied.