Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMany bacteria express phosphoenolpyruvate-dependent phosphotransferase systems (PTS). The mannitol-specific PTS catalyze the uptake and phosphorylation of d-mannitol. The uptake system comprises several genes encoded in the single operon. The expression of the mannitol operon is regulated by a proposed transcriptional factor, mannitol operon repressor (MtlR) that was first studied in Escherichia coli. Here we report the first crystal structures of MtlR from Vibrio parahemeolyticus (Vp-MtlR) and its homolog YggD protein from Shigella flexneri (Sf-YggD). MtlR and YggD belong to the same protein family (Pfam05068). Although Vp-MtlR and Sf-YggD share low sequence identity (22%), their overall structures are very similar, representing a novel all alpha-helical fold, and indicate similar function. However, their lack of any known DNA-binding structural motifs and their unfavorable electrostatic properties imply that MtlR/YggD are unlikely to bind a specific DNA operator directly as proposed earlier. This structural observation is further corroborated by in vitro DNA-binding studies of E. coli MtlR (Ec-MtlR), which detected no interaction of Ec-MtlR with the well characterized mannitol operator/promoter region. Therefore, MtlR/YggD belongs to a new class of transcription factors in bacteria that may regulate gene expression indirectly as a part of a larger transcriptional complex. The mannitol operon repressor MtlR belongs to a new class of transcription regulators in bacteria.,Tan K, Clancy S, Borovilos M, Zhou M, Horer S, Moy S, Volkart LL, Sassoon J, Baumann U, Joachimiak A J Biol Chem. 2009 Dec 25;284(52):36670-9. Epub 2009 Oct 19. PMID:19840941[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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