Structure-based engineering of a minimal porin reveals loop-independent channel closure

Wolfgang Grosse, Georgios Psakis, Barbara Mertins, Philipp Reiss, Dirk Windisch, Felix Brademann, Jochen Bürck, Anne Ulrich, Ulrich Koert, Lars Oliver Essen

Research output: Contribution to journalArticle

16 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)4826-4838
Number of pages13
JournalBiochemistry
Volume53
Issue number29
DOIs
Publication statusPublished - 29 Jul 2014

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Porins
Membrane Proteins
Flickering
Chemical Engineering
Protein Engineering
Amino Acids
Chemical engineering
Ion Channels
Escherichia coli
Stretching
Ions
Membranes
Proteins

Cite this

Grosse, W., Psakis, G., Mertins, B., Reiss, P., Windisch, D., Brademann, F., ... Essen, L. O. (2014). Structure-based engineering of a minimal porin reveals loop-independent channel closure. Biochemistry, 53(29), 4826-4838. https://doi.org/10.1021/bi500660q
Grosse, Wolfgang ; Psakis, Georgios ; Mertins, Barbara ; Reiss, Philipp ; Windisch, Dirk ; Brademann, Felix ; Bürck, Jochen ; Ulrich, Anne ; Koert, Ulrich ; Essen, Lars Oliver. / Structure-based engineering of a minimal porin reveals loop-independent channel closure. In: Biochemistry. 2014 ; Vol. 53, No. 29. pp. 4826-4838.
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Grosse, W, Psakis, G, Mertins, B, Reiss, P, Windisch, D, Brademann, F, Bürck, J, Ulrich, A, Koert, U & Essen, LO 2014, 'Structure-based engineering of a minimal porin reveals loop-independent channel closure', Biochemistry, vol. 53, no. 29, pp. 4826-4838. https://doi.org/10.1021/bi500660q

Structure-based engineering of a minimal porin reveals loop-independent channel closure. / Grosse, Wolfgang; Psakis, Georgios; Mertins, Barbara; Reiss, Philipp; Windisch, Dirk; Brademann, Felix; Bürck, Jochen; Ulrich, Anne; Koert, Ulrich; Essen, Lars Oliver.

In: Biochemistry, Vol. 53, No. 29, 29.07.2014, p. 4826-4838.

Research output: Contribution to journalArticle

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Grosse W, Psakis G, Mertins B, Reiss P, Windisch D, Brademann F et al. Structure-based engineering of a minimal porin reveals loop-independent channel closure. Biochemistry. 2014 Jul 29;53(29):4826-4838. https://doi.org/10.1021/bi500660q