Is DNA transport driven by the proton electrochemical potential difference in the naturally transformable bacteria, Streptococcus pneumoniae?

Abstract

The involvement of Δ μ H + and of its component Δφ in DNA uptake in competent Streptococcus pneumoniae has been addressed. Mutation AmiA9 which reduces specifically U m , alters neither the DNA uptake, nor biological transformation. In addition, no U m -reduced mutants were found among ten independent DNA-uptake-negative mutants. The protonophores TCS and CCCP did not reduce the DNA uptake significantly at pH 7.8, the optimal pH for DNA uptake, but were strongly inhibitors at pH 7. We suggest that the intracellular pH value rather than ΔpH may be determinant for DNA entry in Streptococcus pneumoniae.