4CTD

X-ray structure of an engineered OmpG loop6-deletion

4CTD の概要

• エントリーDOI: 10.2210/pdb4ctd/pdb
• 分子名称: OUTER MEMBRANE PROTEIN G, CHLORIDE ION, (HYDROXYETHYLOXY)TRI(ETHYLOXY)OCTANE (3 entities in total)
• 機能のキーワード: transport protein, ion-channel-engineering, porin
• 由来する生物種: ESCHERICHIA COLI K-12
• 細胞内の位置: Cell outer membrane; Multi-pass membrane protein: P76045
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 65538.22

構造登録者

Grosse, W.,Essen, L.-O. (登録日: 2014-03-13, 公開日: 2014-08-13, 最終更新日: 2023-12-20)

主引用文献

Grosse, W.,Psakis, G.,Mertins, B.,Reiss, P.,Windisch, D.,Brademann, F.,Burck, J.,Ulrich, A.,Koert, U.,Essen, L.
Structure-Based Engineering of a Minimal Porin Reveals Loop- Independent Channel Closure.
Biochemistry, 53:4826-, 2014

PubMed Abstract: Porins, like outer membrane protein G (OmpG) of Escherichia coli, are ideal templates among ion channels for protein and chemical engineering because of their robustness and simple architecture. OmpG shows fast transitions between open and closed states, which were attributed to loop 6 (L6). As flickering limits single-channel-based applications, we pruned L6 by either 8 or 12 amino acids. While the open probabilities of both L6 variants resemble that of native OmpG, their gating frequencies were reduced by 63 and 81%, respectively. Using the 3.2 Å structure of the shorter L6 variant in the open state, we engineered a minimal porin (220 amino acids), where all remaining extramembranous loops were truncated. Unexpectedly, this minimized porin still exhibited gating, but it was 5-fold less frequent than in OmpG. The residual gating of the minimal pore is hence independent of L6 rearrangements and involves narrowing of the ion conductance pathway most probably driven by global stretching-flexing deformations of the membrane-embedded β-barrel.

PubMed: 24988371
DOI: 10.1021/BI500660Q

実験手法

X-RAY DIFFRACTION (3.2 Å)