1
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Ollinger N, Malachova A, Sulyok M, Schütz-Kapl L, Wiesinger N, Krska R, Weghuber J. Combination of DNA barcoding, targeted metabolite profiling and multispectral imaging to identify mold species and metabolites in sliced bread. Future Foods 2022. [DOI: 10.1016/j.fufo.2022.100196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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2
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Ollinger N, Neuhauser C, Schwarzinger B, Wallner M, Schwarzinger C, Blank-Landeshammer B, Hager R, Sadova N, Drotarova I, Mathmann K, Karamouzi E, Panopoulos P, Rimbach G, Lüersen K, Weghuber J, Röhrl C. Anti-Hyperglycemic Effects of Oils and Extracts Derived from Sea Buckthorn - A Comprehensive Analysis Utilizing In Vitro and In Vivo Models. Mol Nutr Food Res 2022; 66:e2101133. [PMID: 35426970 PMCID: PMC9285508 DOI: 10.1002/mnfr.202101133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/14/2022] [Indexed: 12/15/2022]
Abstract
SCOPE Sea buckthorn (Hippophaes rhamnoides) is capable of ameliorating disturbed glucose metabolism in animal models and human subjects. Here, the effect of sea buckthorn oil as well as of extracts of fruits, leaves, and press cake on postprandial glucose metabolism is systematically investigated. METHODS AND RESULTS Sea buckthorn did neither exert decisive effects in an in vitro model of intestinal glucose absorption nor did it alter insulin secretion. However, sea buckthorn stimulates GLUT4 translocation to the plasma membrane comparable to insulin, indicative of increased glucose clearance from the circulation. Isorhamnetin is identified in all sea buckthorn samples investigated and is biologically active in triggering GLUT4 cell surface localization. Consistently, sea buckthorn products lower circulating glucose by ≈10% in a chick embryo model. Moreover, sea buckthorn products fully revert hyperglycemia in the nematode Caenorhabditis elegans while they are ineffective in Drosophila melanogaster under euglycemic conditions. CONCLUSION These data indicate that edible sea buckthorn products as well as by-products are promising resources for hypoglycemic nutrient supplements that increase cellular glucose clearance into target tissues.
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Affiliation(s)
- Nicole Ollinger
- FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, FFoQSI GmbH, Technopark 1D, Tulln, 3430, Austria
| | - Cathrina Neuhauser
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Bettina Schwarzinger
- FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, FFoQSI GmbH, Technopark 1D, Tulln, 3430, Austria.,University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Melanie Wallner
- FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, FFoQSI GmbH, Technopark 1D, Tulln, 3430, Austria
| | - Clemens Schwarzinger
- Johannes Kepler University, Institute for Chemical Technology of Organic Materials, Linz, 4040, Austria
| | - Bernhard Blank-Landeshammer
- FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, FFoQSI GmbH, Technopark 1D, Tulln, 3430, Austria
| | - Roland Hager
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Nadiia Sadova
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Ivana Drotarova
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Katrin Mathmann
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Eugenia Karamouzi
- European Research & Development Rezos Brands, 196 New National Road Patras-Athens, Patras, 26443, Greece
| | - Panagiotis Panopoulos
- European Research & Development Rezos Brands, 196 New National Road Patras-Athens, Patras, 26443, Greece
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Strasse 6, Kiel, 24118, Germany
| | - Kai Lüersen
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Strasse 6, Kiel, 24118, Germany
| | - Julian Weghuber
- FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, FFoQSI GmbH, Technopark 1D, Tulln, 3430, Austria.,University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
| | - Clemens Röhrl
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, 4600, Austria
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3
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Hager R, Müller U, Ollinger N, Weghuber J, Lanzerstorfer P. Subcellular Dynamic Immunopatterning of Cytosolic Protein Complexes on Microstructured Polymer Substrates. ACS Sens 2021; 6:4076-4088. [PMID: 34652152 PMCID: PMC8630788 DOI: 10.1021/acssensors.1c01574] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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Analysis of protein–protein
interactions in living cells
by protein micropatterning is currently limited to the spatial arrangement
of transmembrane proteins and their corresponding downstream molecules.
Here, we present a robust and straightforward method for dynamic immunopatterning
of cytosolic protein complexes by use of an artificial transmembrane
bait construct in combination with microstructured antibody arrays
on cyclic olefin polymer substrates. As a proof, the method was used
to characterize Grb2-mediated signaling pathways downstream of the
epidermal growth factor receptor (EGFR). Ternary protein complexes
(Shc1:Grb2:SOS1 and Grb2:Gab1:PI3K) were identified, and we found
that EGFR downstream signaling is based on constitutively bound (Grb2:SOS1
and Grb2:Gab1) as well as on agonist-dependent protein associations
with transient interaction properties (Grb2:Shc1 and Grb2:PI3K). Spatiotemporal
analysis further revealed significant differences in stability and
exchange kinetics of protein interactions. Furthermore, we could show
that this approach is well suited to study the efficacy and specificity
of SH2 and SH3 protein domain inhibitors in a live cell context. Altogether,
this method represents a significant enhancement of quantitative subcellular
micropatterning approaches as an alternative to standard biochemical
analyses.
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Affiliation(s)
- Roland Hager
- University of Applied Sciences Upper Austria, School of Engineering, 4600 Wels, Austria
| | - Ulrike Müller
- University of Applied Sciences Upper Austria, School of Engineering, 4600 Wels, Austria
| | - Nicole Ollinger
- Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, Head Office: FFoQSI GmbH, Technopark 1C, 3430 Tulln, Austria
| | - Julian Weghuber
- University of Applied Sciences Upper Austria, School of Engineering, 4600 Wels, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, Head Office: FFoQSI GmbH, Technopark 1C, 3430 Tulln, Austria
| | - Peter Lanzerstorfer
- University of Applied Sciences Upper Austria, School of Engineering, 4600 Wels, Austria
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4
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Helmich I, Reinecke K, Meuter K, Simalla N, Ollinger N, Junge R, Lausberg H. Symptoms after sport-related concussions alter gestural functions. J Sci Med Sport 2020; 23:437-441. [DOI: 10.1016/j.jsams.2019.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/27/2019] [Accepted: 11/27/2019] [Indexed: 10/25/2022]
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Müller U, Stübl F, Schwarzinger B, Sandner G, Iken M, Himmelsbach M, Schwarzinger C, Ollinger N, Stadlbauer V, Höglinger O, Kühne T, Lanzerstorfer P, Weghuber J. In Vitro and In Vivo Inhibition of Intestinal Glucose Transport by Guava (Psidium Guajava) Extracts. Mol Nutr Food Res 2018; 62:e1701012. [PMID: 29688623 PMCID: PMC6001447 DOI: 10.1002/mnfr.201701012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/15/2018] [Indexed: 12/21/2022]
Abstract
SCOPE Known pharmacological activities of guava (Psidium guajava) include modulation of blood glucose levels. However, mechanistic details remain unclear in many cases. METHODS AND RESULTS This study investigated the effects of different guava leaf and fruit extracts on intestinal glucose transport in vitro and on postprandial glucose levels in vivo. Substantial dose- and time-dependent glucose transport inhibition (up to 80%) was observed for both guava fruit and leaf extracts, at conceivable physiological concentrations in Caco-2 cells. Using sodium-containing (both glucose transporters, sodium-dependent glucose transporter 1 [SGLT1] and glucose transporter 2 [GLUT2], are active) and sodium-free (only GLUT2 is active) conditions, we show that inhibition of GLUT2 was greater than that of SGLT1. Inhibitory properties of guava extracts also remained stable after digestive juice treatment, indicating a good chemical stability of the active substances. Furthermore, we could unequivocally show that guava extracts significantly reduced blood glucose levels (≈fourfold reduction) in a time-dependent manner in vivo (C57BL/6N mice). Extracts were characterized with respect to their main putative bioactive compounds (polyphenols) using HPLC and LC-MS. CONCLUSION The data demonstrated that guava leaf and fruit extracts can potentially contribute to the regulation of blood glucose levels.
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Affiliation(s)
- Ulrike Müller
- University of Applied Sciences Upper Austria4600WelsAustria
| | - Flora Stübl
- University of Applied Sciences Upper Austria4600WelsAustria
| | - Bettina Schwarzinger
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | - Georg Sandner
- University of Applied Sciences Upper Austria4600WelsAustria
| | | | - Markus Himmelsbach
- Johannes Kepler UniversityInstitute for Analytical Chemistry4040LinzAustria
| | - Clemens Schwarzinger
- Johannes Kepler UniversityInstitute for Chemical Technology of Organic Materials4040LinzAustria
| | - Nicole Ollinger
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | - Verena Stadlbauer
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | | | | | | | - Julian Weghuber
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
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Sachelaru I, Winter L, Knyazev DG, Zimmermann M, Vogt A, Kuttner R, Ollinger N, Siligan C, Pohl P, Koch HG. YidC and SecYEG form a heterotetrameric protein translocation channel. Sci Rep 2017; 7:101. [PMID: 28273911 PMCID: PMC5427846 DOI: 10.1038/s41598-017-00109-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/08/2017] [Indexed: 11/26/2022] Open
Abstract
The heterotrimeric SecYEG complex cooperates with YidC to facilitate membrane protein insertion by an unknown mechanism. Here we show that YidC contacts the interior of the SecY channel resulting in a ligand-activated and voltage-dependent complex with distinct ion channel characteristics. The SecYEG pore diameter decreases from 8 Å to only 5 Å for the YidC-SecYEG pore, indicating a reduction in channel cross-section by YidC intercalation. In the presence of a substrate, YidC relocates to the rim of the pore as indicated by increased pore diameter and loss of YidC crosslinks to the channel interior. Changing the surface charge of the pore by incorporating YidC into the channel wall increases the anion selectivity, and the accompanying change in wall hydrophobicity is liable to alter the partition of helices from the pore into the membrane. This could explain how the exit of transmembrane domains from the SecY channel is facilitated by YidC.
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Affiliation(s)
- Ilie Sachelaru
- grid.5963.9Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104 Germany ,grid.5963.9Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, 79104 Freiburg, Germany
| | - Lukas Winter
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Denis G. Knyazev
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Mirjam Zimmermann
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Andreas Vogt
- grid.5963.9Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104 Germany ,grid.5963.9Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, 79104 Freiburg, Germany ,grid.5963.9Spemann-Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Roland Kuttner
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Nicole Ollinger
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Christine Siligan
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020, Linz, Austria.
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104, Germany. .,Spemann-Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany.
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7
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Karner A, Nimmervoll B, Plochberger B, Klotzsch E, Horner A, Knyazev DG, Kuttner R, Winkler K, Winter L, Siligan C, Ollinger N, Pohl P, Preiner J. Tuning membrane protein mobility by confinement into nanodomains. Nat Nanotechnol 2017; 12:260-266. [PMID: 27842062 PMCID: PMC5734611 DOI: 10.1038/nnano.2016.236] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/30/2016] [Indexed: 05/04/2023]
Abstract
High-speed atomic force microscopy (HS-AFM) can be used to visualize function-related conformational changes of single soluble proteins. Similar studies of single membrane proteins are, however, hampered by a lack of suitable flat, non-interacting membrane supports and by high protein mobility. Here we show that streptavidin crystals grown on mica-supported lipid bilayers can be used as porous supports for membranes containing biotinylated lipids. Using SecYEG (protein translocation channel) and GlpF (aquaglyceroporin), we demonstrate that the platform can be used to tune the lateral mobility of transmembrane proteins to any value within the dynamic range accessible to HS-AFM imaging through glutaraldehyde-cross-linking of the streptavidin. This allows HS-AFM to study the conformation or docking of spatially confined proteins, which we illustrate by imaging GlpF at sub-molecular resolution and by observing the motor protein SecA binding to SecYEG.
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Affiliation(s)
- Andreas Karner
- Center for Advanced Bioanalysis GmbH, Gruberstr. 40-42, 4020 Linz, Austria
| | | | - Birgit Plochberger
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020 Linz, Austria
| | - Enrico Klotzsch
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
| | - Andreas Horner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Denis G. Knyazev
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Roland Kuttner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Klemens Winkler
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Lukas Winter
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Christine Siligan
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Nicole Ollinger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Johannes Preiner
- Center for Advanced Bioanalysis GmbH, Gruberstr. 40-42, 4020 Linz, Austria
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8
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Erokhova L, Horner A, Ollinger N, Siligan C, Pohl P. The Sodium Glucose Cotransporter SGLT1 Is an Extremely Efficient Facilitator of Passive Water Transport. J Biol Chem 2016; 291:9712-20. [PMID: 26945065 PMCID: PMC4850308 DOI: 10.1074/jbc.m115.706986] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/04/2016] [Indexed: 11/06/2022] Open
Abstract
The small intestine is void of aquaporins adept at facilitating vectorial water transport, and yet it reabsorbs ∼8 liters of fluid daily. Implications of the sodium glucose cotransporter SGLT1 in either pumping water or passively channeling water contrast with its reported water transporting capacity, which lags behind that of aquaporin-1 by 3 orders of magnitude. Here we overexpressed SGLT1 in MDCK cell monolayers and reconstituted the purified transporter into proteoliposomes. We observed the rate of osmotic proteoliposome deflation by light scattering. Fluorescence correlation spectroscopy served to assess (i) SGLT1 abundance in both vesicles and plasma membranes and (ii) flow-mediated dilution of an aqueous dye adjacent to the cell monolayer. Calculation of the unitary water channel permeability, pf, yielded similar values for cell and proteoliposome experiments. Neither the absence of glucose or Na(+), nor the lack of membrane voltage in vesicles, nor the directionality of water flow grossly altered pf Such weak dependence on protein conformation indicates that a water-impermeable occluded state (glucose and Na(+) in their binding pockets) lasts for only a minor fraction of the transport cycle or, alternatively, that occlusion of the substrate does not render the transporter water-impermeable as was suggested by computational studies of the bacterial homologue vSGLT. Although the similarity between the pf values of SGLT1 and aquaporin-1 makes a transcellular pathway plausible, it renders water pumping physiologically negligible because the passive flux would be orders of magnitude larger.
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Affiliation(s)
- Liudmila Erokhova
- From the Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria
| | - Andreas Horner
- From the Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria
| | - Nicole Ollinger
- From the Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria
| | - Christine Siligan
- From the Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria
| | - Peter Pohl
- From the Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria
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9
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Horner A, Zocher F, Preiner J, Ollinger N, Siligan C, Akimov SA, Pohl P. The mobility of single-file water molecules is governed by the number of H-bonds they may form with channel-lining residues. Sci Adv 2015; 1:e1400083. [PMID: 26167541 PMCID: PMC4496530 DOI: 10.1126/sciadv.1400083] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/12/2015] [Indexed: 05/19/2023]
Abstract
Channel geometry governs the unitary osmotic water channel permeability, pf, according to classical hydrodynamics. Yet, pf varies by several orders of magnitude for membrane channels with a constriction zone that is one water molecule in width and four to eight molecules in length. We show that both the pf of those channels and the diffusion coefficient of the single-file waters within them are determined by the number NH of residues in the channel wall that may form a hydrogen bond with the single-file waters. The logarithmic dependence of water diffusivity on NH is in line with the multiplicity of binding options at higher NH densities. We obtained high-precision pf values by (i) having measured the abundance of the reconstituted aquaporins in the vesicular membrane via fluorescence correlation spectroscopy and via high-speed atomic force microscopy, and (ii) having acquired the vesicular water efflux from scattered light intensities via our new adaptation of the Rayleigh-Gans-Debye equation.
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Affiliation(s)
- Andreas Horner
- Johannes Kepler University Linz, Institute of Biophysics, Gruberstr. 40, 4020 Linz, Austria
| | - Florian Zocher
- Johannes Kepler University Linz, Institute of Biophysics, Gruberstr. 40, 4020 Linz, Austria
| | - Johannes Preiner
- Center for Advanced Bioanalysis GmbH (CBL), Gruberstr. 40, 4020 Linz, Austria
| | - Nicole Ollinger
- Johannes Kepler University Linz, Institute of Biophysics, Gruberstr. 40, 4020 Linz, Austria
| | - Christine Siligan
- Johannes Kepler University Linz, Institute of Biophysics, Gruberstr. 40, 4020 Linz, Austria
| | - Sergey A. Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31/5, 119071 Moscow, Russia
- National University of Science and Technology “MISiS,” Leninsky pr., 4, 119049 Moscow, Russia
| | - Peter Pohl
- Johannes Kepler University Linz, Institute of Biophysics, Gruberstr. 40, 4020 Linz, Austria
- Corresponding author. E-mail:
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10
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Preiner J, Horner A, Karner A, Ollinger N, Siligan C, Pohl P, Hinterdorfer P. High-speed AFM images of thermal motion provide stiffness map of interfacial membrane protein moieties. Nano Lett 2015; 15:759-63. [PMID: 25516527 PMCID: PMC4296598 DOI: 10.1021/nl504478f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 12/11/2014] [Indexed: 05/20/2023]
Abstract
The flexibilities of extracellular loops determine ligand binding and activation of membrane receptors. Arising from fluctuations in inter- and intraproteinaceous interactions, flexibility manifests in thermal motion. Here we demonstrate that quantitative flexibility values can be extracted from directly imaging the thermal motion of membrane protein moieties using high-speed atomic force microscopy (HS-AFM). Stiffness maps of the main periplasmic loops of single reconstituted water channels (AqpZ, GlpF) revealed the spatial and temporal organization of loop-stabilizing intraproteinaceous H-bonds and salt bridges.
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Affiliation(s)
- Johannes Preiner
- Center
for Advanced Bioanalysis GmbH, Gruberstrasse 40, 4020 Linz, Austria
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
- E-mail:
| | - Andreas Horner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Andreas Karner
- Center
for Advanced Bioanalysis GmbH, Gruberstrasse 40, 4020 Linz, Austria
| | - Nicole Ollinger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Christine Siligan
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Peter Hinterdorfer
- Center
for Advanced Bioanalysis GmbH, Gruberstrasse 40, 4020 Linz, Austria
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
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11
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12
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Winter L, Knyazev D, Ollinger N, Vogt A, Siligan C, Koch HG, Pohl P. YidC Alters Conductivity and Ion Selectivity of the Bacterial Translocation Channel SecYEG. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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13
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Knyazev DG, Lents A, Krause E, Ollinger N, Siligan C, Papinski D, Winter L, Horner A, Pohl P. The bacterial translocon SecYEG opens upon ribosome binding. J Biol Chem 2013; 288:17941-6. [PMID: 23645666 PMCID: PMC3689939 DOI: 10.1074/jbc.m113.477893] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In co-translational translocation, the ribosome funnel and the channel of the protein translocation complex SecYEG are aligned. For the nascent chain to enter the channel immediately after synthesis, a yet unidentified signal triggers displacement of the SecYEG sealing plug from the pore. Here, we show that ribosome binding to the resting SecYEG channel triggers this conformational transition. The purified and reconstituted SecYEG channel opens to form a large ion-conducting channel, which has the conductivity of the plug deletion mutant. The number of ion-conducting channels inserted into the planar bilayer per fusion event roughly equals the number of SecYEG channels counted by fluorescence correlation spectroscopy in a single proteoliposome. Thus, the open probability of the channel must be close to unity. To prevent the otherwise lethal proton leak, a closed post-translational conformation of the SecYEG complex bound to a ribosome must exist.
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Affiliation(s)
- Denis G Knyazev
- Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria
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14
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Knyazev D, Lents A, Winter L, Ollinger N, Siligan C, Pohl P. Transport of Small Molecules across the Bacterial Translocation Channel SecYEG. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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