Zq. Hao et al., Cloning, expression, and characterization of cadmium and manganese uptake genes from Lactobacillus plantarum, APPL ENVIR, 65(11), 1999, pp. 4746-4752
An Mn2+ and Cd2+ uptake gene, mntA, was cloned from Lactobacillus plantarum
ATCC 14917 into Escherichia coli, Its expression conferred on E. coli cell
s increased Cd2+ sensitivity as well as energy dependent Cd2+ uptake activi
ty. Both transcription and translation of mntA were induced by Mn2+ starvat
ion in L, plantarum, as indicated by reverse transcriptase PCR and immunobl
otting, Two Cd2+ uptake systems have been identified in L, plantarum: one i
s a high-affinity Mn2+ and Cd2+ uptake system that is expressed in Mn2+-sta
rved cells, and the other is a nonsaturable Cd2+ uptake system that is expr
essed in Cd2+-sufficient cells (Z, Hao, H. R, Reiske, and D, B, Wilson, App
l, Environ, Microbiol, 65:592-99, 1999), MntA was not detected in an Mn2+ d
ependent mutant of L, plantarum which had lost high-affinity Mn2+ and Cd2uptake activity. The results suggest that mntA is the gene encoding the hig
h-affinity Mn2+ and Cd2+ transporter. On the basis of its predicted amino a
cid sequence, MntA belongs to the family of P-type cation-translocating ATP
ases, The topology and potential Mn2+- and Cd2+-binding sites of MntA are d
iscussed. A second clone containing a low-affinity Cd2+ transport system wa
s also isolated.