5m28

Maltodextrin binding protein MalE1 from L. casei BL23 bound to maltotriose

spinqualitylabelsall models 5m28, resolution 1.08Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5m28 is a 1 chain structure with sequence from Lacticaseibacillus casei. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.079Å Ligands: CL, GLC, PRD_900009 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function B0L7B0_LACCA Publication Abstract from PubMed Catabolite repression is a mechanism that enables bacteria to control carbon utilization. As part of this global regulatory network, components of the phosphoenolpyruvate:carbohydrate phosphotransferase system inhibit the uptake of less favorable sugars when a preferred carbon source such as glucose is available. This process is termed inducer exclusion. In bacteria belonging to the phylum Firmicutes, HPr, phosphorylated at serine 46 (P-Ser46-HPr) is the key player but its mode of action is elusive. To address this question at the level of purified protein components, we have chosen a homolog of the Escherichia coli maltose/maltodextrin ATP-binding cassette transporter from Lactobacillus casei (MalE1-MalF1G1K12 ) as a model system. We show that the solute binding protein, MalE1, binds linear and cyclic maltodextrins but not maltose. Crystal structures of MalE1 complexed with these sugars provide a clue why maltose is not a substrate. P-Ser46-HPr inhibited MalE1/maltotetraose-stimulated ATPase activity of the transporter incorporated in proteoliposomes. Furthermore, cross-linking experiments revealed that P-Ser46-HPr contacts the nucleotide-binding subunit, MalK1, in proximity to the Walker A motif. However, P-Ser46-HPr did not block binding of ATP to MalK1. Together, our findings provide first biochemical evidence that P-Ser-HPr arrests the transport cycle by preventing ATP hydrolysis at the MalK1 subunits of the transporter. Inducer exclusion in Firmicutes: insights into the regulation of a carbohydrate ATP binding cassette transporter from Lactobacillus casei BL23 by the signal transducing protein P-Ser46-HPr.,Homburg C, Bommer M, Wuttge S, Hobe C, Beck S, Dobbek H, Deutscher J, Licht A, Schneider E Mol Microbiol. 2017 Jul;105(1):25-45. doi: 10.1111/mmi.13680. Epub 2017 Apr 18. PMID:28370477 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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