scholarly journals Drug-bound and -free outward-facing structures of a multidrug ABC exporter point to a swing mechanism

2021 ◽  
Author(s):  
vincent Chaptal ◽  
Veronica Zampieri ◽  
Benjamin Wiseman ◽  
Cedric Orelle ◽  
Juliette Martin ◽  
...  
Keyword(s):  
Abc Transporters ◽  
Drug Transport ◽  
Rhodamine 6G ◽  
Drug Binding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Outer Leaflet ◽  
Molecular Features ◽  
Binding Cavity ◽  
Dynamics Simulations

Multidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved two ATP-Mg2+-bound outward-facing (OF) conformations of the Bacillus subtilis (homodimeric) BmrA, one by X-ray crystallography without drug, and another by single-particle cryo-EM with rhodamine 6G (R6G). Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1-2 of one monomer and TM5[prime]-6[prime] of the other. R6G induces a rearrangement of TM1-2, highlighting a flexibility that was confirmed by H/D exchange and molecular dynamics simulations. The latter also shows a fast post-release occlusion of the cavity driven by hydrophobicity. Altogether, these data support a new swing mechanism for drug transport.

scholarly journals Elucidation of Lipid Binding Sites on Lung Surfactant Protein A Using X-ray Crystallography, Mutagenesis, and Molecular Dynamics Simulations

Biochemistry ◽  
2016 ◽  
Vol 55 (26) ◽  
pp. 3692-3701 ◽  
Author(s):  
Boon Chong Goh ◽  
Huixing Wu ◽  
Michael J. Rynkiewicz ◽  
Klaus Schulten ◽  
Barbara A. Seaton ◽  
...  
Keyword(s):  
Binding Sites ◽  
Lung Surfactant ◽  
Protein A ◽  
Surfactant Protein ◽  
Lipid Binding ◽  
Surfactant Protein A ◽  
X Ray ◽  
X Ray Crystallography ◽  
Lung Surfactant Protein ◽  
Dynamics Simulations

scholarly journals Structure and mechanism of ATP-binding cassette transporters

2008 ◽  
Vol 364 (1514) ◽  
pp. 239-245 ◽  
Author(s):  
Kaspar P Locher
Keyword(s):  
Abc Transporters ◽  
Integral Membrane Proteins ◽  
Atp Binding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Binding Domains ◽  
Mechanistic Insight ◽  
Future Challenges ◽  
Hydrolysis Of ◽  
Atp Binding Cassette

ATP-binding cassette (ABC) transporters constitute a large superfamily of integral membrane proteins that includes both importers and exporters. In recent years, several structures of complete ABC transporters have been determined by X-ray crystallography. These structures suggest a mechanism by which binding and hydrolysis of ATP by the cytoplasmic, nucleotide-binding domains control the conformation of the transmembrane domains and therefore which side of the membrane the translocation pathway is exposed to. A basic, conserved two-state mechanism can explain active transport of both ABC importers and ABC exporters, but various questions remain unresolved. In this article, I will review some of the crystal structures and the mechanistic insight gained from them. Future challenges for a better understanding of the mechanism of ABC transporters will be outlined.

scholarly journals High-throughput cloning and expression of human ABC transporters in Baculovirus/Insect Cell system customized for X-ray crystallography studies

2014 ◽  
Author(s):  
Rafael Resende ◽  
Chitra Shintre ◽  
Claire Strain-Damerell ◽  
Shubhashish Mukhopadhyay ◽  
Nicola Burgess-Brown ◽  
...  
Keyword(s):  
High Throughput ◽  
Abc Transporters ◽  
Insect Cell ◽  
Cell System ◽  
Cloning And Expression ◽  
X Ray ◽  
X Ray Crystallography

scholarly journals Mixed Chirality α-Helix in a Stapled Bicyclic and a Linear Antimicrobial Peptide Revealed by X-Ray Crystallography

2021 ◽  
Author(s):  
stéphane Baeriswyl ◽  
Hippolyte Personne ◽  
Ivan Di Bonaventura ◽  
Thilo Köhler ◽  
Christian van Delden ◽  
...  
Keyword(s):  
Bioactive Peptides ◽  
Multidrug Resistant ◽  
Isobutyric Acid ◽  
Resistant Bacteria ◽  
X Ray ◽  
X Ray Crystallography ◽  
Left Handed ◽  
Amino Isobutyric Acid ◽  
Α Helix ◽  
Dynamics Simulations

<p>The peptide α-helix is right-handed when containing amino acids with L-chirality, and left-handed with D-chirality. What happens in between is largely unknown, however α-helices have not been reported with mixed chirality sequences unless a strong non-natural helix inducer such as amino-isobutyric acid was used. Herein we report the discovery of a membrane disruptive amphiphilic antimicrobial undecapeptide containing seven L- and four D-residues forming a stable right-handed α-helix in stapled bicyclic and linear forms. The α-helical fold is evidenced by X-ray crystallography and supported in solution by circular dichroism spectra as well as molecular dynamics simulations. The linear mixed chirality peptide is as active as the L-sequence against multidrug resistant bacteria but shows no hemolysis and full stability against serum proteolysis. Searching for mixed chirality analogs preserving folding might be generally useful to optimize α-helical bioactive peptides. </p>

scholarly journals Mixed Chirality α-Helix in a Stapled Bicyclic and a Linear Antimicrobial Peptide Revealed by X-Ray Crystallography

2021 ◽  
Author(s):  
stéphane Baeriswyl ◽  
Hippolyte Personne ◽  
Ivan Di Bonaventura ◽  
Thilo Köhler ◽  
Christian van Delden ◽  
...  
Keyword(s):  
Bioactive Peptides ◽  
Multidrug Resistant ◽  
Isobutyric Acid ◽  
Resistant Bacteria ◽  
X Ray ◽  
X Ray Crystallography ◽  
Left Handed ◽  
Amino Isobutyric Acid ◽  
Α Helix ◽  
Dynamics Simulations

<p>The peptide α-helix is right-handed when containing amino acids with L-chirality, and left-handed with D-chirality. What happens in between is largely unknown, however α-helices have not been reported with mixed chirality sequences unless a strong non-natural helix inducer such as amino-isobutyric acid was used. Herein we report the discovery of a membrane disruptive amphiphilic antimicrobial undecapeptide containing seven L- and four D-residues forming a stable right-handed α-helix in stapled bicyclic and linear forms. The α-helical fold is evidenced by X-ray crystallography and supported in solution by circular dichroism spectra as well as molecular dynamics simulations. The linear mixed chirality peptide is as active as the L-sequence against multidrug resistant bacteria but shows no hemolysis and full stability against serum proteolysis. Searching for mixed chirality analogs preserving folding might be generally useful to optimize α-helical bioactive peptides. </p>

scholarly journals A pharmacological master key mechanism that unlocks the selectivity filter gate in K+channels

Science ◽  
2019 ◽  
Vol 363 (6429) ◽  
pp. 875-880 ◽  
Author(s):  
Marcus Schewe ◽  
Han Sun ◽  
Ümit Mert ◽  
Alexandra Mackenzie ◽  
Ashley C. W. Pike ◽  
...  
Keyword(s):  
Selectivity Filter ◽  
Rational Drug Design ◽  
Related Gene ◽  
K Channels ◽  
X Ray ◽  
Voltage Gated ◽  
X Ray Crystallography ◽  
Rational Drug ◽  
Dynamics Simulations ◽  
Pore Domain

Potassium (K+) channels have been evolutionarily tuned for activation by diverse biological stimuli, and pharmacological activation is thought to target these specific gating mechanisms. Here we report a class of negatively charged activators (NCAs) that bypass the specific mechanisms but act as master keys to open K+channels gated at their selectivity filter (SF), including many two-pore domain K+(K2P) channels, voltage-gated hERG (human ether-à-go-go–related gene) channels and calcium (Ca2+)–activated big-conductance potassium (BK)–type channels. Functional analysis, x-ray crystallography, and molecular dynamics simulations revealed that the NCAs bind to similar sites below the SF, increase pore and SF K+occupancy, and open the filter gate. These results uncover an unrecognized polypharmacology among K+channel activators and highlight a filter gating machinery that is conserved across different families of K+channels with implications for rational drug design.

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