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Svensson, Stefan
Alternative names
Publications (9 of 9) Show all publications
Ottosson, N., Wu, X., Nolting, A., Karlsson, U., Lund, P.-E., Ruda, K., . . . Elinder, F. (2015). Resin-acid derivatives as potent electrostatic openers of voltage-gated K channels and suppressors of neuronal excitability. Scientific Reports, 5(13278)
Open this publication in new window or tab >>Resin-acid derivatives as potent electrostatic openers of voltage-gated K channels and suppressors of neuronal excitability
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2015 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, no 13278Article in journal (Refereed) Published
Abstract [en]

Voltage-gated ion channels generate cellular excitability, cause diseases when mutated, and act as drug targets in hyperexcitability diseases, such as epilepsy, cardiac arrhythmia and pain. Unfortunately, many patients do not satisfactorily respond to the present-day drugs. We found that the naturally occurring resin acid dehydroabietic acid (DHAA) is a potent opener of a voltage-gated K channel and thereby a potential suppressor of cellular excitability. DHAA acts via a non-traditional mechanism, by electrostatically activating the voltage-sensor domain, rather than directly targeting the ion-conducting pore domain. By systematic iterative modifications of DHAA we synthesized 71 derivatives and found 32 compounds more potent than DHAA. The most potent compound, Compound 77, is 240 times more efficient than DHAA in opening a K channel. This and other potent compounds reduced excitability in dorsal root ganglion neurons, suggesting that resin-acid derivatives can become the first members of a new family of drugs with the potential for treatment of hyperexcitability diseases.

Place, publisher, year, edition, pages
Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group, 2015
National Category
Clinical Medicine Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-121307 (URN)10.1038/srep13278 (DOI)000359905300001 ()26299574 (PubMedID)
Note

Funding Agencies|Swedish Research Council; Swedish Brain Foundation; Swedish Heart-Lung Foundation; ALF; County Council of Ostergotland

Available from: 2015-09-16 Created: 2015-09-14 Last updated: 2018-01-25Bibliographically approved
Fyrner, T., Svensson, S. C. .. & Konradsson, P. (2012). Synthesis of tri-, penta-, and hepta-saccharides, functionalized with Orthogonally N-Protected Amino residues at the reducing and non-reducing ends. Tetrahedron, 68(33), 6712-6720
Open this publication in new window or tab >>Synthesis of tri-, penta-, and hepta-saccharides, functionalized with Orthogonally N-Protected Amino residues at the reducing and non-reducing ends
2012 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, no 33, p. 6712-6720Article in journal (Refereed) Published
Abstract [en]

The synthesis of four bifunctionalized orthogonally N-protected oligosaccharides derived from lactose and mannose, intended as cross-linking derivatives, is described. The amino sugar at the non-reducing end is derivatized with an N-Boc-protected glycine moiety, and further connected to either a mannose (1→6) disaccharide or (1→3) lactose units (one, two or three) resulting in tri-, penta-, or heptasaccharides. All of the synthesized oligosaccharides have an Nbenzyloxycarbonyl-aminoethyl residue at the reducing end. The fully orthogonal N-Boc/N-Cbz protection group pattern enables further conjugation/derivatization and results in a hydrophilic cross-linking molecule. It was found that the order of the final synthetic steps were crucial to avoid acyl migration. A suitable amide coupling protocol has been applied to introduce the NBoc-protected glycine moiety in alcoholic solvent. The synthesized oligosaccharides will provide a model system to investigate the influence of length, structure and flexibility. The function of the cross-linked substituents thereby provide valuable insights into the role as a spacer molecule.

Keywords
Glycosylation, glycosidation, oligosaccharide synthesis, spacer molecules, orthogonally protected, carbohydrates, bifunctionalized
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-76730 (URN)10.1016/j.tet.2012.05.118 (DOI)000306618400009 ()
Available from: 2012-04-18 Created: 2012-04-18 Last updated: 2017-12-07Bibliographically approved
Östblom, M., Valiokas, R., Konradsson, P., Svensson, S., Liedberg, B., Garrett, M. & Allara, D. (2006). Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments. Journal of Physical Chemistry B, 110(4), 1830-1836
Open this publication in new window or tab >>Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments
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2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1830-1836Article in journal (Refereed) Published
Abstract [en]

The nucleation and phase behavior of ultrathin D2O-ice overlayers have been studied on oligo(ethylene glycol) (OEG)-terminated and hydroxyl self-assembled monolayers (SAMs) at low temperatures in ultrahigh vacuum. Infrared reflection-absorption spectroscopy (IRAS) is used to characterize the ice overlayers, the SAMs, and the interactions occurring between the ice and the SAM surfaces. Spectral simulations, based on optical models in conjunction with Maxwell Garnett effective medium theory, point out the importance of including voids in the modeling of the ice structures, with void fractions reaching 60% in some overlayers. The kinetics of the phase transition from amorphous-like to crystalline-like ice upon isothermal annealing at 140 K is found to depend on the conformational state of the supporting OEG SAM surface. The rate is fast on the helical OEG SAMs and slow on the corresponding all-trans SAMs. This difference in kinetics is most likely due to a pronounced D2O interpenetration and binding to the all-trans segments of the ethylene glycol portion of the SAM. No such penetration and binding was observed on the helical OEG SAM. © 2006 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-50302 (URN)10.1021/jp056007q (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Svedhem, S., Ohberg, L., Borrelli, S., Valiokas, R., Andersson, M., Oscarson, S., . . . Konradsson, P. (2002). Synthesis and self-assembly of globotriose derivatives: A model system for studies of carbohydrate-protein interactions. Langmuir, 18(7), 2848-2858
Open this publication in new window or tab >>Synthesis and self-assembly of globotriose derivatives: A model system for studies of carbohydrate-protein interactions
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2002 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, no 7, p. 2848-2858Article in journal (Refereed) Published
Abstract [en]

Self-assembled monolayers (SAMs) on gold exposing a-D-Galp-(1 ? 4)-ß-D-Galp-(1?4)-ß-D-Glcp (globotriose) are described. A synthetic pathway for the preparation of the bioactive carbohydrate globotriose coupled directly to bis(16-hydroxyhexadecanyl) disulfide ((HOC16H32S)2), as well as via tetra- or di(ethylene glycol) spacers, was developed. The SAMs were characterized by ellipsometry, contact angle goniometry, infrared reflection-absorption spectroscopy, and by their interactions with monoclonal antibodies. The ellipsometry measurements of mixed SAMs revealed thicknesses between 22 and 40 Å, depending on the ratio between carbohydrate and non-carbohydrate disulfides in the preparation solution. When the solution contained 10% or more of the carbohydrate adsorbate, the modified gold substrates displayed total wetting. Infrared reflection-absorption spectroscopy conferred well-ordered SAMs with a high degree of crystallinity. Furthermore, two monoclonal antibodies (IgM, MAHI 419 and IgG, MAHI 5) showed different affinity for mixed SAMs depending on the fraction and the structure of the carbohydrate component used (globotriose or globotriose tetra(ethylene glycol)), with the largest amount of protein bound for MAHI 419 at 1-10% of surface carbohydrate. These results demonstrate the usefulness of the SAM approach to explore molecular details such as the effect of a spacer or antigen distribution on antibody interactions at interfaces.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47042 (URN)10.1021/la015643m (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Lindberg, J., Svensson, S., Pahlsson, P. & Konradsson, P. (2002). Synthesis of galactoglycerolipids found in the HT29 human colon carcinoma cell line. Tetrahedron, 58(25), 5109-5117
Open this publication in new window or tab >>Synthesis of galactoglycerolipids found in the HT29 human colon carcinoma cell line
2002 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 58, no 25, p. 5109-5117Article in journal (Refereed) Published
Abstract [en]

Synthesis of three galactoglycerolipids (3-O-(ß-D-galactopyranosyl)-1-O-hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-sn-glycerol), and the corresponding glycerolipid (1-O-hexadecyl-2-O-palmitoyl-sn-glycerol) is described. The first two compounds were recently identified in the human colon carcinoma cell line HT29. The three-carbon synthon (S)-glycidol was used for construction of the glycerol moiety. Glycosylation of (S)-glycidol with protected galactosyl and digalactosyl donors produced galactosyl and digalactosyl glycidols. Lewis acid catalyzed opening of the epoxide produced protected galactosyl and digalactosyl glycerolipids. Deprotection, or palmitoylation followed by deprotection, yielded the target compounds. The corresponding glycerolipid was synthesized analogously and an oxidation-reduction procedure for tritiation was developed. The synthesized compounds will be used in studies of the role of galactosyl glycerolipids in differentiation and colon cancer development. © 2002 Elsevier Science Ltd. All rights reserved.

Keywords
Galactoglycerolipids, Glycidol, Glycosylation, Oligosaccharide synthesis, Thioglycosides
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-46981 (URN)10.1016/S0040-4020(02)00473-8 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Valiokas, R., Svedhem, S., Östblom, M., Svensson, S. & Liedberg, B. (2001). Influence of specific intermolecular interactions on the self-assembly and phase behavior of oligo(ethylene glycol)-terminated alkanethiolates on gold. Journal of Physical Chemistry B, 105(23), 5459-5469
Open this publication in new window or tab >>Influence of specific intermolecular interactions on the self-assembly and phase behavior of oligo(ethylene glycol)-terminated alkanethiolates on gold
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2001 (English)In: Journal of Physical Chemistry B, ISSN 1089-5647, Vol. 105, no 23, p. 5459-5469Article in journal (Refereed) Published
Abstract [en]

A comparative study of the self-assembly and phase behavior of seven different oligo(ethylene glycol) (OEG)-terminated alkanethiols on polycrystalline gold surfaces is presented. The general structure of the compounds is HS(CH2)m-X-EGn, where m = 11, 15, n = 2, 4, 6, and the linkages X are amide (-CONH-), ester (-COO-), or ether (-O-) groups. The amide and ester groups give rise to the intermolecular hydrogen bonding and dipole-dipole interactions, respectively, whereas the ether lacks specific interactions. The results from contact angle goniometry, null ellipsometry, and infrared reflection-absorption spectroscopy (IRAS) indicate that the intermolecular interactions can be partly used to control the conformation and order of the OEG portion of the self-assembled monolayers (SAMs). It is shown that the lateral hydrogen bonding stabilizes the all-trans conformation of the EG4 tails in the SAMs. Further on, the mechanism behind the thermal phase behavior of the OEG SAMs is investigated using temperature-programmed IRAS in ultrahigh vacuum. In the present study we show that the earlier reported helix-to-all-trans conformational transition at 60°C in the SAM of HS(CH2)15CONH-EG6 (Valiokas, R., Östblom, M., Svedhem, S., Svensson, S. C. T., Liedberg, B. J. Phys. Chem. 2000, 104, 7565-7569.) is a result of the particular molecular design of the SAMs through the specifically built-in lateral hydrogen bonds. A shortening of the alkyl chain to 11 methylenes has no effect on the amide-EG6 phase behavior. Contrary, the ester- and ether- containing SAMs undergo a melting type of transitions at 52 and 68°C, respectively, similar to that observed for poly(ethylene glycol).

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47353 (URN)10.1021/jp004441g (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2011-01-13
Benesch, J., Svedhem, S., Svensson, S., Valiokas, R., Liedberg, B. & Tengvall, P. (2001). Protein adsorption to oligo(ethylene glycol) self-assembled monolayers: Experiments with fibrinogen, heparinized plasma, and serum. Journal of Biomaterials Science. Polymer Edition, 12(6), 581-597
Open this publication in new window or tab >>Protein adsorption to oligo(ethylene glycol) self-assembled monolayers: Experiments with fibrinogen, heparinized plasma, and serum
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2001 (English)In: Journal of Biomaterials Science. Polymer Edition, ISSN 0920-5063, E-ISSN 1568-5624, Vol. 12, no 6, p. 581-597Article in journal (Refereed) Published
Abstract [en]

Low protein adsorption is believed advantageous for blood-contacting materials and ethylene glycols (EG)-based polymeric compounds are often attached to surfaces for this purpose. In the present study, the adsorption of fibrinogen, serum, and plasma were studied by ellipsometry on a series of well-defined oligo(EG) terminated alkane-thiols self-assembled on gold. The layers were prepared with compounds of the general structure HS-(CH2)15-CONH-EGn, where n = 2, 4, and 6. Methoxy-terminated tri(EG) undecanethiol and hydroxyl-terminated hexadecanethiol self-assembled monolayers (SAMs) were used as references. The results clearly demonstrate that the adsorption depends on the experimental conditions with small amounts of fibrinogen adsorbing from a single protein solution, but larger amounts of proteins from serum and plasma. The adsorption of fibrinogen and blood plasma decreased with an increasing number of EG repeats and was temperature-dependent. Significantly less serum adsorbed to methoxy tri(EG) than to hexa(EG) and more proteins remained on the latter surface after incubation in a sodium dodecyl sulfate (SDS) solution, indicating a looser protein binding to the methoxy-terminated surface. All surfaces adsorbed complement factor 3(C3) from serum and plasma, although no surface-mediated complement activation was observed. The present study points to the importance of a careful choice of the protein model system before general statements regarding the protein repellant properties of potential surfaces can be made.

Keywords
Complement, Fibrinogen, Heparinized plasma, Oligo(ethylene glycol), Protein adsorption, Self-assembled monolayers, Serum
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47265 (URN)10.1163/156856201316883421 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Svedhem, S., Enander, K., Karlsson, M., Sjöbom, H., Liedberg, B., Löfås, S., . . . Lundström, I. (2001). Subtle differences in dissociation rates of interactions between destabilized human carbonic anhydrase II mutants and immobilized benzenesulfonamide inhibitors probed by a surface plasmon resonance biosensor. Analytical Biochemistry, 296(2), 188-196
Open this publication in new window or tab >>Subtle differences in dissociation rates of interactions between destabilized human carbonic anhydrase II mutants and immobilized benzenesulfonamide inhibitors probed by a surface plasmon resonance biosensor
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2001 (English)In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 296, no 2, p. 188-196Article in journal (Refereed) Published
Abstract [en]

The development of commercial biosensors based on surface plasmon resonance has made possible careful characterization of biomolecular interactions. Here, a set of destabilized human carbonic anhydrase II (HCA II) mutants was investigated with respect to their interaction kinetics with two different immobilized benzenesulfonamide inhibitors. Point mutations were located distantly from the active site, and the destabilization energies were up to 23 kJ/mol. The dissociation rate of wild-type HCA II, as determined from the binding to the inhibitor with higher affinity, was 0.019 s−1. For the mutants, dissociation rates were faster (0.022–0.025 s−1), and a correlation between faster dissociation and a high degree of destabilization was observed. We interpreted these results in terms of increased dynamics of the tertiary structures of the mutants. This interpretation was supported by entropy determinations, showing that the entropy of the native structure significantly increased upon destabilization of the protein molecule. Our findings demonstrate the applicability of modern biosensor technology in the study of subtle details in molecular interaction mechanisms, such as the long-range effect of point mutations on interaction kinetics.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-25364 (URN)10.1006/abio.2001.5301 (DOI)9807 (Local ID)9807 (Archive number)9807 (OAI)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
Svedhem, S., Hollander, C.-A., Shi, J., Konradsson, P., Liedberg, B. & Svensson, S. (2001). Synthesis of a series of oligo(ethylene glycol)-terminated alkanethiol amides designed to address structure and stability of biosensing interfaces. Journal of Organic Chemistry, 66(13), 4494-4503
Open this publication in new window or tab >>Synthesis of a series of oligo(ethylene glycol)-terminated alkanethiol amides designed to address structure and stability of biosensing interfaces
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2001 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, no 13, p. 4494-4503Article in journal (Refereed) Published
Abstract [en]

A strategy for the synthesis of a series of closely related oligo(ethylene glycol)-terminated alkanethiol amides (principally HS(CH2)mCONH(CH2CH2O) nH, m = 2, 5, 11, 15, n = 1, 2, 4, 6, 8, 10, 12) and analogous esters has been developed. These compounds were made to study the structure and stability of self-assembled monolayers (SAMs) on gold in the prospect of designing new biosensing interfaces. For this purpose, monodisperse heterofunctional oligo(ethylene glycols) with up to 12 units were prepared. Selective monoacylation of the symmetrical tetra- and hexa(ethylene glycol) diols as their mesylates with the use of silver(I) oxide was performed. The synthetic approach was based on carbodiimide couplings of various oligo(ethylene glycol) derivatives to ?-(acetylthio) carboxylic acids via a terminal amino or hydroxyl function. SAM structures on gold were studied with respect to thickness, wettability (water contact angles ~30°), and conformation. A good fit was obtained for the relation between monolayer thickness (d) and the number of units in the oligo(ethylene glycol) chain (n): d = 2.8n + 21.8 (Å). Interestingly, the corresponding infrared spectroscopy analysis showed a dramatic change in conformation of the oligomeric chains from all-trans (n = 4) to helical (n = 6) conformation. A crystalline helical structure was observed in the SAMs for n > 6.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47339 (URN)10.1021/jo0012290 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
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