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- *************************************************
- * Sodium:galactoside symporter family signature *
- *************************************************
-
- It has been shown [1] that integral membrane proteins that mediate the intake
- of a wide variety of molecules with the concomitant uptake of sodium ions
- (sodium symporters) can be grouped, on the basis of sequence and functional
- similarities into a number of distinct families. One of these families is
- known as the sodium:galactoside symporter family (SGF) and currently consists
- of the following proteins:
-
- - The melibiose carrier (gene melB) from a variety of enterobacteria. This
- protein is responsible for melibiose transport and is capable of using
- hydrogen, sodium, and lithium cations as coupling cations for cotransport.
- - The lactose permease from Lactobacillus (gene lacS or lacY). This protein
- is responsible for the transport of beta-galactosides into the cell, with
- the concomitant export of a proton. It consists of two domains; a N-
- terminal SGF domain and a C-terminal domain that resembles that of enzyme
- IIA of the PEP:sugar phosphotransferase system.
- - Escherichia coli hypothetical protein yicJ.
- - Escherichia coli hypothetical protein yihO.
- - Escherichia coli hypothetical protein yihP.
-
- Like sugar transport proteins, these integral membrane proteins are predicted
- to comprise twelve membrane spanning domains. As a signature pattern we
- selected a highly conserved region which is located in a cytoplasmic loop
- between the second and third transmembrane regions. This region starts with
- a conserved aspartate which has been shown [2], in melB, to be important for
- the activity of the protein.
-
- -Consensus pattern: D-x(3)-G-x(3)-[DN]-x(6,8)-G-K-F-[KR]-P-[FYW]-[LIVM](2)-x-
- [GSTA](2)
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Expert(s) to contact by email: Reizer J.
- jreizer@ucsd.edu
-
- -Last update: October 1993 / First entry.
-
- [ 1] Reizer J., Reizer A., Saier M.H. Jr.
- Submitted(1993).
-