Abstract
We isolated a mutant of Escherichia coli which was defective in an Na+/H+ antiporter and grew poorly under alkaline conditions [Ishikawa, T., Hama, EL, Tsuda, T., and Tsuchiya, T. (1987) J. BioL Chenu 262, 7443-7446]. Later, it was concluded that the defective Na+/H+ antiporter in the mutant was the NhaB system, and the nhaB gene was mapped to 25.6 min on the E. coli chromosome [Thelen, P., Tsuchiya, T., and Goldberg, E.B. (1991) J. Bacteriol. 173, 6553-6557]. We found that the NhaB-defective cells cannot grow in a high pH medium. Furthermore, intracellular pH in the mutant cells was almost the same as extracellular pH between 7.9 and 9.1, that is, intracellular pH was not regulated at this pH range. On the other hand, intracellular pH of the wild-type cells was maintained at about 7.6 when the extracellular pH was between 7.6 and 8.5. Thus, the NhaB Na+/H+ antiporter is essential for the regulation of intracellular pH under alkaline conditions in E. coli. Introduction of nhaA gene into the mutant cells increased Na+/H+ antiporter activity, but did not restore the defective growth and defective intracellular pH regulation under alkaline conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 285-290 |
| Number of pages | 6 |
| Journal | Journal of Biochemistry |
| Volume | 116 |
| Issue number | 2 |
| Publication status | Published - Aug 1994 |
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Keywords
- Escherichia coli
- NhaB antiporter
- PH regulation
- Sodium ion/proton antiporter
ASJC Scopus subject areas
- Statistics, Probability and Uncertainty
- Applied Mathematics
- Physiology (medical)
- Radiology Nuclear Medicine and imaging
- Molecular Biology
- Biochemistry
Cite this
The NhaB Na+/H+ antiporter is essential for intracellular pH regulation under alkaline conditions in escherichia coli. / Shimamoto, Toshi; Inaba, Kei; Thelen, Paul; Ishikawa, Tetsuya; Goldberg, Edward B.; Tsuda, Masaaki; Tsuchiya, Tomofusa.
In: Journal of Biochemistry, Vol. 116, No. 2, 08.1994, p. 285-290.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The NhaB Na+/H+ antiporter is essential for intracellular pH regulation under alkaline conditions in escherichia coli
AU - Shimamoto, Toshi
AU - Inaba, Kei
AU - Thelen, Paul
AU - Ishikawa, Tetsuya
AU - Goldberg, Edward B.
AU - Tsuda, Masaaki
AU - Tsuchiya, Tomofusa
PY - 1994/8
Y1 - 1994/8
N2 - We isolated a mutant of Escherichia coli which was defective in an Na+/H+ antiporter and grew poorly under alkaline conditions [Ishikawa, T., Hama, EL, Tsuda, T., and Tsuchiya, T. (1987) J. BioL Chenu 262, 7443-7446]. Later, it was concluded that the defective Na+/H+ antiporter in the mutant was the NhaB system, and the nhaB gene was mapped to 25.6 min on the E. coli chromosome [Thelen, P., Tsuchiya, T., and Goldberg, E.B. (1991) J. Bacteriol. 173, 6553-6557]. We found that the NhaB-defective cells cannot grow in a high pH medium. Furthermore, intracellular pH in the mutant cells was almost the same as extracellular pH between 7.9 and 9.1, that is, intracellular pH was not regulated at this pH range. On the other hand, intracellular pH of the wild-type cells was maintained at about 7.6 when the extracellular pH was between 7.6 and 8.5. Thus, the NhaB Na+/H+ antiporter is essential for the regulation of intracellular pH under alkaline conditions in E. coli. Introduction of nhaA gene into the mutant cells increased Na+/H+ antiporter activity, but did not restore the defective growth and defective intracellular pH regulation under alkaline conditions.
AB - We isolated a mutant of Escherichia coli which was defective in an Na+/H+ antiporter and grew poorly under alkaline conditions [Ishikawa, T., Hama, EL, Tsuda, T., and Tsuchiya, T. (1987) J. BioL Chenu 262, 7443-7446]. Later, it was concluded that the defective Na+/H+ antiporter in the mutant was the NhaB system, and the nhaB gene was mapped to 25.6 min on the E. coli chromosome [Thelen, P., Tsuchiya, T., and Goldberg, E.B. (1991) J. Bacteriol. 173, 6553-6557]. We found that the NhaB-defective cells cannot grow in a high pH medium. Furthermore, intracellular pH in the mutant cells was almost the same as extracellular pH between 7.9 and 9.1, that is, intracellular pH was not regulated at this pH range. On the other hand, intracellular pH of the wild-type cells was maintained at about 7.6 when the extracellular pH was between 7.6 and 8.5. Thus, the NhaB Na+/H+ antiporter is essential for the regulation of intracellular pH under alkaline conditions in E. coli. Introduction of nhaA gene into the mutant cells increased Na+/H+ antiporter activity, but did not restore the defective growth and defective intracellular pH regulation under alkaline conditions.
KW - Escherichia coli
KW - NhaB antiporter
KW - PH regulation
KW - Sodium ion/proton antiporter
UR - http://www.scopus.com/inward/record.url?scp=0028101275&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028101275&partnerID=8YFLogxK
M3 - Article
C2 - 7822245
AN - SCOPUS:0028101275
VL - 116
SP - 285
EP - 290
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 2
ER -