5MKB

Maltodextrin binding protein MalE1 from L. casei BL23 without ligand

5MKB の概要

• エントリーDOI: 10.2210/pdb5mkb/pdb
• 関連するPDBエントリー: 5M28
• 分子名称: MalE1 (2 entities in total)
• 機能のキーワード: carbohydrate binding protein, lactobacillus casei, sugar binding protein
• 由来する生物種: Lactobacillus casei
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 324037.87

構造登録者

Homburg, C.,Bommer, M.,Wuttge, S.,Hobe, C.,Beck, S.,Dobbek, H.,Deutscher, J.,Licht, A.,Schneider, E. (登録日: 2016-12-03, 公開日: 2017-07-05, 最終更新日: 2024-01-17)

主引用文献

Homburg, C.,Bommer, M.,Wuttge, S.,Hobe, C.,Beck, S.,Dobbek, H.,Deutscher, J.,Licht, A.,Schneider, E.
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.
Mol. Microbiol., 105:25-45, 2017

PubMed Abstract: 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-MalF1G1K1 ) 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.

PubMed: 28370477
DOI: 10.1111/mmi.13680

実験手法

X-RAY DIFFRACTION (1.698 Å)