Structure of the maltodextrin-uptake locus of Streptococcus pneumoniae. Correlation to the Escherichia coli maltose regulon.
The mechanism of induction of the maltose/maltodextrin regulon of the Gram-positive bacterium Streptococcus pneumoniae seems to be different to the positively controlled maltose regulons of the enteric bacteria Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium. In this work, we report on the structure of the S. pneumoniae genes involved in maltodextrin uptake malX, malC and malD. Comparisons of the amino acid sequences encoded by these genes indicate that they are homologous to the E. coli MalE periplasmic maltose binding protein and the two maltose permeases MalG and MalF. The analysis of transcription start points indicates that malXCD could be transcribed from a single consensus promoter sequence. Northern analysis of the mRNA molecules pertaining to this region reveals that the transcript encompassing all these three genes is apparently cleaved at a large putative mRNA secondary structure, yielding two mRNA molecules. The smaller of these molecules would include only the malX gene while a larger fragment spans through malC and malD. The processing of mRNA has not been reported in the Gram-negative maltose regulons, and may suggest either a less evolved or a divergent system for the control of gene expression of this regulon in S. pneumoniae.
Puyet
A
A
Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.
Espinosa
M
M
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008320:Maltose / Q000235:genetics / Q000378:metabolism*; D058619:Maltose-Binding Proteins; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009690:Nucleic Acid Conformation; D033902:Periplasmic Binding Proteins; D011134:Polysaccharides / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C080819:MalC protein, Streptococcus pneumoniae; C080820:MalD protein, Streptococcus pneumoniae; C461619:MalE protein, E coli; C079123:MalG protein, E coli; C080821:MalX protein, Streptococcus pneumoniae; D058619:Maltose-Binding Proteins; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011134:Polysaccharides; D012333:RNA, Messenger; C461599:maltose transport system, E coli; D008320:Maltose; C008315:maltodextrin; C021534:maltose permease