Interactions of a Bacterial RND Transporter with a Transmembrane Small Protein in a Lipid Environment

AbstractThe small protein AcrZ in Escherichia coli interacts with the transmembrane portion of the multidrug efflux pump AcrB and increases the resistance of the bacterium to a subset of the antibiotic substrates of that transporter. It is not clear how the physical association of the two proteins selectively changes activity of the pump for defined substrates. Here, we report cryo-EM structures of AcrB and the AcrBZ complex in lipid environments, and comparisons suggest that conformational changes occur in the drug binding pocket as a result of AcrZ binding. Simulations indicate that cardiolipin preferentially interacts with the AcrBZ complex, due to increased contact surface, and we observe that the drug sensitivity of bacteria lacking AcrZ is exacerbated when combined with cardiolipin deficiency. Taken together, the data suggest that AcrZ and lipid cooperate to allosterically modulate the activity of AcrB. This mode of regulation by a small protein and lipid may occur for other membrane proteins.

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Faculty Opinions recommendation of Comparisons of NMR spectral quality and success in crystallization demonstrate that NMR and X-ray crystallography are complementary methods for small protein structure determination.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1029453.344422 ◽

2005 ◽

Author(s):

Deyou Zheng

Keyword(s):

Protein Structure ◽

Structure Determination ◽

Protein Structure Determination ◽

Spectral Quality ◽

Small Protein ◽

X Ray ◽

Complementary Methods ◽

X Ray Crystallography

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Faculty Opinions recommendation of Fusion to a homo-oligomeric scaffold allows cryo-EM analysis of a small protein.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726601979.793522374 ◽

2016 ◽

Author(s):

Maya Topf

Keyword(s):

Small Protein

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Molecular pathways of Interferon–Stimulated Gene 15: Implications in cancer

Current Protein and Peptide Science ◽

10.2174/1389203721999201208200747 ◽

2020 ◽

Vol 21 ◽

Author(s):

Angeles C. Tecalco–Cruz

Keyword(s):

Posttranslational Modification ◽

Human Interferon ◽

Molecular Pathways ◽

Biological Processes ◽

Small Protein ◽

Target Proteins ◽

Central Elements ◽

Cancer Types ◽

Interferon Stimulated Gene 15

Abstract:: Human interferon–stimulated gene 15 (ISG15) is a 15–kDa ubiquitin–like protein that can be detected as either free ISG15 or covalently associated with its target proteins through a process termed ISGylation. Interestingly, extracellular free ISG15 has been proposed as a cytokine–like protein, whereas ISGylation is a posttranslational modification. ISG15 is a small protein with implications in some biological processes and pathologies that include cancer. This review highlights the findings of both free ISG15 and protein ISGylation involved in several molecular pathways, emerging as central elements in some cancer types.

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Co-Translational Insertion of Aquaporins into Liposome for Functional Analysis via an E. coli Based Cell-Free Protein Synthesis System

Cells ◽

10.3390/cells8111325 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1325 ◽

Cited By ~ 1

Author(s):

Ke Yue ◽

Tran Nam Trung ◽

Yiyong Zhu ◽

Ralf Kaldenhoff ◽

Lei Kai

Keyword(s):

Functional Analysis ◽

Membrane Proteins ◽

Fluorescent Protein ◽

Water Channel ◽

New Approach ◽

E Coli ◽

Straightforward Method ◽

Lipid Environment ◽

Green Fluorescent ◽

Eukaryotic Organisms

Aquaporins are important and well-studied water channel membrane proteins. However, being membrane proteins, sample preparation for functional analysis is tedious and time-consuming. In this paper, we report a new approach for the co-translational insertion of two aquaporins from Escherichia coli and Nicotiana tabacum using the CFPS system. This was done in the presence of liposomes with a modified procedure to form homogenous proteo-liposomes suitable for functional analysis of water permeability using stopped-flow spectrophotometry. Two model aquaporins, AqpZ and NtPIP2;1, were successfully incorporated into the liposome in their active forms. Shifted green fluorescent protein was fused to the C-terminal part of AqpZ to monitor its insertion and status in the lipid environment. This new fast approach offers a fast and straightforward method for the functional analysis of aquaporins in both prokaryotic and eukaryotic organisms.

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Signaling of cell fate determination by the TPD1 small protein and EMS1 receptor kinase

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0708795105 ◽

2008 ◽

Vol 105 (6) ◽

pp. 2220-2225 ◽

Cited By ~ 106

Author(s):

G. Jia ◽

X. Liu ◽

H. A. Owen ◽

D. Zhao

Keyword(s):

Cell Fate ◽

Cell Fate Determination ◽

Receptor Kinase ◽

Small Protein ◽

Fate Determination

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The small protein MafG plays a critical role in MC3T3-E1 cell apoptosis induced by simulated microgravity and radiation

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2021.03.133 ◽

2021 ◽

Vol 555 ◽

pp. 175-181

Author(s):

Honghui Wang ◽

Jingjing Dong ◽

Gaozhi Li ◽

Yingjun Tan ◽

Hai Zhao ◽

...

Keyword(s):

Cell Apoptosis ◽

Simulated Microgravity ◽

Critical Role ◽

Small Protein

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The Profound Influence of Lipid Composition on the Catalysis of the Drug Target NADH Type II Oxidoreductase

Membranes ◽

10.3390/membranes11050363 ◽

2021 ◽

Vol 11 (5) ◽

pp. 363

Author(s):

Albert Godoy-Hernandez ◽

Duncan G. G. McMillan

Keyword(s):

Acyl Chain ◽

Cellular Respiration ◽

Type Ii ◽

Nadh:Quinone Oxidoreductase ◽

Chain Composition ◽

Membrane Bound ◽

Lipid Environment ◽

Lipid Specificity ◽

Mediated Catalysis ◽

Quinone Pool

Lipids play a pivotal role in cellular respiration, providing the natural environment in which an oxidoreductase interacts with the quinone pool. To date, it is generally accepted that negatively charged lipids play a major role in the activity of quinone oxidoreductases. By changing lipid compositions when assaying a type II NADH:quinone oxidoreductase, we demonstrate that phosphatidylethanolamine has an essential role in substrate binding and catalysis. We also reveal the importance of acyl chain composition, specifically c14:0, on membrane-bound quinone-mediated catalysis. This demonstrates that oxidoreductase lipid specificity is more diverse than originally thought and that the lipid environment plays an important role in the physiological catalysis of membrane-bound oxidoreductases.

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