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PMID:19294451

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Citation

Peng, Y, Kumar, S, Hernandez, RL, Jones, SE, Cadle, KM, Smith, KP and Varela, MF (2009) Evidence for the transport of maltose by the sucrose permease, CscB, of Escherichia coli. J. Membr. Biol. 228:79-88

Abstract

The purpose of this study was to examine the sugar recognition and transport properties of the sucrose permease (CscB), a secondary active transporter from Escherichia coli. We tested the hypothesis that maltose transport is conferred by the wild-type CscB transporter. Cells of E. coli HS4006 harboring pSP72/cscB were red on maltose MacConkey agar indicator plates. We were able to measure "downhill" maltose transport and establish definitive kinetic behavior for maltose entry in such cells. Maltose was an effective competitor of sucrose transport in cells with CscB, suggesting that the respective maltose and sucrose binding sites and translocation pathways through the CscB channel overlap. Accumulation ("uphill" transport) of maltose by cells with CscB was profound, demonstrating active transport of maltose by CscB. Sequencing of cscB encoded on plasmid pSP72/cscB used in cells for transport studies indicate an unaltered primary CscB structure, ruling out the possibility that mutation conferred maltose transport by CscB. We conclude that maltose is a bona fide substrate for the sucrose permease of E. coli. Thus, future studies of sugar binding, transport, and permease structure should consider maltose, as well as sucrose.

Links

PubMed PMC2661012 Online version:10.1007/s00232-009-9161-9

Keywords

Amino Acid Sequence; Biological Transport; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Kinetics; Maltose/metabolism; Membrane Transport Proteins/genetics; Membrane Transport Proteins/metabolism; Molecular Sequence Data; Mutation; Sequence Homology, Amino Acid; Sucrose/metabolism

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

ECOLX:CSCB

GO:0008643: carbohydrate transport

ECO:0000314:

P

Figure 3

complete


See also

References

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