3HPI

Crystal structure of maltose-binding protein mutant with bound sucrose

3HPI の概要

• エントリーDOI: 10.2210/pdb3hpi/pdb
• 関連するPDBエントリー: 1ANF
• 関連するBIRD辞書のPRD_ID: PRD_900003
• 分子名称: Maltose-binding periplasmic protein, beta-D-fructofuranose-(2-1)-alpha-D-glucopyranose, ZINC ION, ... (5 entities in total)
• 機能のキーワード: sugar binding protein, periplasmic binding protein, mbp, sugar transport, transport
• 由来する生物種: Escherichia coli
• 細胞内の位置: Periplasm: P0AEX9
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 83011.88

構造登録者

Gould, A.D.,Shilton, B.H. (登録日: 2009-06-04, 公開日: 2010-02-09, 最終更新日: 2023-09-06)

主引用文献

Gould, A.D.,Shilton, B.H.
Studies of the maltose transport system reveal a mechanism for coupling ATP hydrolysis to substrate translocation without direct recognition of substrate.
J.Biol.Chem., 285:11290-11296, 2010

PubMed Abstract: The ATPase activity of the maltose transporter (MalFGK(2)) is dependent on interactions with the maltose-binding protein (MBP). To determine whether direct interactions between the translocated sugar and MalFGK(2) are important for the regulation of ATP hydrolysis, we used an MBP mutant (sMBP) that is able to bind either maltose or sucrose. We observed that maltose- and sucrose-bound sMBP stimulate equal levels of MalFGK(2) ATPase activity. Therefore, the ATPase activity of MalFGK(2) is coupled to translocation of maltose solely by interactions between MalFGK(2) and MBP. For both maltose and sucrose, the ability of sMBP to stimulate the MalFGK(2) ATPase was greatly reduced compared with wild-type MBP, indicating that the mutations in sMBP have interfered with important interactions between MBP and MalFGK(2). High resolution crystal structure analysis of sMBP shows that in the closed conformation with bound sucrose, three of four mutations are buried, and the fourth causes only a minor change in the accessible surface. In contrast, in the open form of sMBP, all of the mutations are accessible, and the main chain of Tyr(62)-Gly(69) is destabilized and occupies an alternative conformation due to the W62Y mutation. On this basis, the compromised ability of sMBP to stimulate ATP hydrolysis by MalFGK(2) is most likely due to a disruption of interactions between MalFGK(2) and the open, rather than the closed, conformation of sMBP. Modeling the open sMBP structure bound to MalFGK(2) in the transition state for ATP hydrolysis points to an important site of interaction and suggests a mechanism for coupling ATP hydrolysis to substrate translocation that is independent of the exact structure of the substrate.

PubMed: 20147285
DOI: 10.1074/jbc.M109.089078

実験手法

X-RAY DIFFRACTION (2 Å)