원문정보
초록
영어
A putative Na+/H+ antiporter (SCO3185, designated as sha4) from Streptomyces coelicolor
A3(2) was overexpressed in E. coli and its roles under various stress conditions were
demonstrated. For pH shock stress test, the sha4 transformant was grown in LB and an pH
shock was applied by switching the pH from 7.0 to 3.5~10. It was found that the transformant
showed a higher tolerance to pH shock than the control. For salt stress test, sha4 transformant
was grown in LB at various concentrations (0, 200, 400, 600, 800 mM) of Na+ and K+. No
significant sha4 dosage effect was observed up to 200 mM of salt concentration for both of
Na+ and K+. The sha4 transformant was clearly observed to have a higher salt tolerance than
the control over 400 mM. Time profiling of intracellular [Na+] and [K+] during salt shock
condition showed that sha4 had Na+ and K+ extrusion activity. These findings are, although
preliminary yet, are meaningful evidence that sha4 could be a real Na+/H+ or K+/H+ antiporter.
[This work was supported by a grant of R01-2006-000-10860-0 from the Basic Research
Program of the Ministry of Education, Science and Technology, Korea]