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Sequencing of the Streptococcus thermophilus F(1)-ATPase operon
Abstract
Streptococcus thermophilus is a lactic acid bacterium used for the production of fermented dairy products. S. thermophilus, like other lactic acid bacteria, produces lactic acid, and therefore must be able to tolerate an acidic, low pH environment. The F$\sb1$F$\sb0$-proton translocating ATPase is largely responsible for enabling this organism to maintain a near-neutral intracellular environment while the exterior pH continues to decrease. The goal of the present research was to further our knowledge and understanding of the F$\sb1$F$\sb0$-ATPase in S. thermophilus, especially with regard to the genes coding for this enzyme. The chromosomal DNA region 3$\sp\prime$ to the atpF gene in the ATPase operon was amplified by the use of PCR. Three fragments of 1.4 kb, 2.4 kb, and 1.7 kb were generated, cloned and sequenced. Sequence analysis revealed five open reading frames extending the length of the F$\sb1$ portion of the operon. In addition, the correct start codons for the five genes were located as well as the putative stop codons. The peptides translated from these open reading frames had high similarity ($\alpha$ and $\beta$ genes $>$90%) to ATPase gene products from Enterococcus hirae and other bacteria. Possible regulatory regions were also identified within the DNA sequence. An atp gene cluster from Streptococcus thermophilus was able to complement an Escherichia coli atpH mutant that was ordinarily unable to grow on succinate minimal medium. Complementation of the ATPase mutant was observed and the subunit from the F$\sb1$ portion of the Streptococcus thermophilus ATPase formed a functional association with the F$\sb1$ subunits of the Escherichia coli enzyme. This information will prove to be very useful for further investigations of the ATPase in Streptococcus thermophilus. The next step will be to produce ATPase defective mutants in Streptococcus using this information with the end result being a greater understanding of the function and regulation of this enzyme.
Subject Area
Food science|Molecular biology|Microbiology
Recommended Citation
Boothe, Theresa Gerise, "Sequencing of the Streptococcus thermophilus F(1)-ATPase operon" (1997). ETD collection for University of Nebraska-Lincoln. AAI9815880.
https://digitalcommons.unl.edu/dissertations/AAI9815880