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Baltzer, Lars
Publications (10 of 30) Show all publications
Kondori, N., Baltzer, L., Dolphin, G. & Mattsby-Baltzer, I. (2011). Fungicidal activity of human lactoferrin-derived peptides based on the antimicrobial alpha beta region. INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS, 37(1), 51-57
Open this publication in new window or tab >>Fungicidal activity of human lactoferrin-derived peptides based on the antimicrobial alpha beta region
2011 (English)In: INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS, ISSN 0924-8579, Vol. 37, no 1, p. 51-57Article in journal (Refereed) Published
Abstract [en]

Owing to the increasing number of infections in hospitalised patients caused by resistant strains of fungi, there is a need to develop new therapeutic agents for these infections. Naturally occurring antimicrobial peptides may constitute models for developing such agents. A modified peptide sequence (CFQWKRAM-RKVR; HLopt2) based on amino acid residues 20-31 of the N-terminal end of human lactoferrin (hLF) as well as a double-sized human lactoferricin-like peptide (amino acid residues 16-40; HLBD1) were investigated for their antifungal activities in vitro and in vivo. By in vitro assay, HLopt2 was fungicidal at concentrations of 12.5-25 mu g/mL against Cryptococcus neoformans, Candida albicans, Candida krusei, Candida kefyr and Candida parapsilosis, but not against Candida glabrata. HLopt2 was demonstrated to have andgt;= 16-fold greater killing activity than HLBD1. By inducing some helical formation caused by lactam bridges or by extending the assay time (from 2 h to 20 h), HLBD1 became almost comparable with HLopt2 in its fungicidal activity. Killing of C. albicans yeast cells by HLopt2 was rapid and was accompanied by cytoplasmic and mitochondrial membrane permeabilisation as well as formation of deep pits on the yeast cell surface. In a murine C. albicans skin infection model, atopic treatment with the peptides resulted in significantly reduced yields of Candida from the infected skin areas. The antifungal activities of HLopt2 in vitro and in vivo suggest possible potential as a therapeutic agent against most Candida spp. and C. neoformans. The greatly improved antifungal effect of the lactam-modified HLBD1 indicates the importance of amphipathic helix formation for lethal activity.

Place, publisher, year, edition, pages
Elsevier Science B.V., Amsterdam., 2011
Keywords
Fungicidal activity, Peptide, Lactoferricin, Candida albicans
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-64386 (URN)10.1016/j.ijantimicag.2010.08.020 (DOI)000285332700010 ()
Available from: 2011-01-21 Created: 2011-01-21 Last updated: 2011-01-21
Haversen, L., Kondori, N., Baltzer, L., A Hanson, L. A., Dolphin, G., Duner, K. & Mattsby-Baltzer, I. (2010). Structure-Microbicidal Activity Relationship of Synthetic Fragments Derived from the Antibacterial alpha-Helix of Human Lactoferrin. Antimicrobial Agents and Chemotherapy, 54(1), 418-425
Open this publication in new window or tab >>Structure-Microbicidal Activity Relationship of Synthetic Fragments Derived from the Antibacterial alpha-Helix of Human Lactoferrin
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2010 (English)In: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 54, no 1, p. 418-425Article in journal (Refereed) Published
Abstract [en]

There is a need for new microbicidal agents with therapeutic potential due to antibiotic resistance in bacteria and fungi. In this study, the structure-microbicidal activity relationship of amino acid residues 14 to 31 (sequence 14-31) from the N-terminal end, corresponding to the antibacterial alpha-helix of human lactoferrin (LF), was investigated by downsizing, alanine scanning, and substitution of amino acids. Microbicidal analysis (99% killing) was performed by a microplate assay using Escherichia coli, Staphylococcus aureus, and Candida albicans as test organisms. Starting from the N-terminal end, downsizing of peptide sequence 14-31 showed that the peptide sequence 19-31 (KCFQWQRNMRKVR, HL9) was the optimal length for antimicrobial activity. Furthermore, HL9 bound to lipid A/lipopolysaccharide, as shown by neutralizing endotoxic activity in a Limulus assay. Alanine scanning of peptide sequence 20-31 showed that Cys20, Trp23, Arg28, Lys29, or Arg31 was important for expressing full killing activity, particularly against C. albicans. Substituting the neutral hydrophilic amino acids Gln24 and Asn26 for Lys and Ala (HLopt2), respectively, enhanced microbicidal activity significantly against all test organisms compared to the amino acids natural counterpart, also, in comparison with HL9, HLopt2 had more than 10-fold-stronger fungicidal activity. Furthermore, HLopt2 was less affected by metallic salts than HL9. The microbicidal activity of HLopt2 was slightly reduced only at pH 7.0, as tested in the pH range of 4.5 to 7.5. The results showed that the microbicidal activity of synthetic peptide sequences, based on the antimicrobial alpha-helix region of LF, can be significantly enhanced by optimizing the length and substitution of neutral amino acids at specific positions, thus suggesting a sequence lead with therapeutic potential.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-52879 (URN)10.1128/AAC.00908-09 (DOI)
Available from: 2010-01-13 Created: 2010-01-12 Last updated: 2017-12-12
Höst, G., Razkin, J., Baltzer, L. & Jonsson, B.-H. (2007). Combined Enzyme and Substrate Design: Grafting of a Cooperative Two-Histidine Catalytic Motif into a Protein Targeted at the Scissile Bond in a Designed Ester Substrate. ChemBioChem (Print), 8(13), 1570-1576
Open this publication in new window or tab >>Combined Enzyme and Substrate Design: Grafting of a Cooperative Two-Histidine Catalytic Motif into a Protein Targeted at the Scissile Bond in a Designed Ester Substrate
2007 (English)In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 8, no 13, p. 1570-1576Article in journal (Refereed) Published
Abstract [en]

A histidine-based, two-residue reactive site for the catalysis of hydrolysis of designed sulfonamide-containing para-nitrophenyl esters has been engineered into a scaffold protein. A matching substrate was designed to exploit the natural active site of human carbonic anhydrase II (HCAII) for well-defined binding. In this we took advantage of the high affinity between the active site zinc atom and sulfonamides. The ester substrate was designed to position the scissile bond in close proximity to the His64 residue in the scaffold protein. Three potential sites for grafting the catalytic His-His pair were identified, and the corresponding N62H/H64, F131H/V135H and L198H/P202H mutants were constructed. The most efficient variant, F131H/V135H, has a maximum kcat/KM value of approximately 14 000 M-1 s-1, with a kcat value that is increased by a factor of 3 relative to that of the wild-type HCAII, and by a factor of over 13 relative to the H64A mutant. The results show that an esterase can be designed in a stepwise way by a combination of substrate design and grafting of a designed catalytic motif into a well-defined substrate binding site.

Keywords
chiral resolution, enzyme catalysis, hydrolysis, mutagenesis, protein engineering
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-12861 (URN)10.1002/cbic.200600540 (DOI)
Available from: 2008-01-09 Created: 2008-01-09 Last updated: 2017-12-14
Aili, D., Enander, K., Baltzer, L. & Liedberg, B. (2007). Synthetic de novo designed polypeptides for control of nanoparticle assembly and biosensing. In: Bionanotechnology; from self-assembly to cellbiology,2007 (pp. 532). London: Biochemical Society Transactions
Open this publication in new window or tab >>Synthetic de novo designed polypeptides for control of nanoparticle assembly and biosensing
2007 (English)In: Bionanotechnology; from self-assembly to cellbiology,2007, London: Biochemical Society Transactions , 2007, p. 532-Conference paper, Published paper (Refereed)
Abstract [en]

     

Place, publisher, year, edition, pages
London: Biochemical Society Transactions, 2007
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-43346 (URN)73599 (Local ID)73599 (Archive number)73599 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2014-10-08
Aili, D., Enander, K., Rydberg, J., Lundström, I., Baltzer, L. & Liedberg, B. (2006). Aggregation-Induced Folding of a de novo Designed Polypeptide Immobilized on Gold Nanoparticles. Journal of the American Chemical Society, 128(7), 2194 -2195
Open this publication in new window or tab >>Aggregation-Induced Folding of a de novo Designed Polypeptide Immobilized on Gold Nanoparticles
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2006 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 128, no 7, p. 2194 -2195Article in journal (Refereed) Published
Abstract [en]

This communication reports the first steps in the construction of a novel, nanoparticle-based hybrid material for biomimetic and biosensor applications. Gold nanoparticles were modified with synthetic polypeptides to enable control of the particle aggregation state in a switchable manner, and particle aggregation was, in turn, found to induce folding of the immobilized peptides.

Place, publisher, year, edition, pages
ACS Publications, 2006
Keywords
Not aviable
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:liu:diva-14041 (URN)10.1021/ja057056j (DOI)
Available from: 2006-09-28 Created: 2006-09-28 Last updated: 2018-01-13Bibliographically approved
Rydberg, J., Vijayalekshmi, S. & Baltzer, L. (2006). Intrinsically unstructured proteins by design: electrostatic interactions can control binding, folding and function of a helix-loop-helix heterodimer.
Open this publication in new window or tab >>Intrinsically unstructured proteins by design: electrostatic interactions can control binding, folding and function of a helix-loop-helix heterodimer
2006 (English)Article in journal (Refereed) Submitted
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14038 (URN)
Available from: 2006-09-28 Created: 2006-09-28
Aili, D., Enander, K., Lundström, I., Baltzer, L. & Liedberg, B. (2006). Towards novel functional materials and sensors using de novo designed polypeptides on gold nanoparticles. In: Europtrode VIII,2006.
Open this publication in new window or tab >>Towards novel functional materials and sensors using de novo designed polypeptides on gold nanoparticles
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2006 (English)In: Europtrode VIII,2006, 2006Conference paper, Published paper (Other academic)
Abstract [en]

    

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-42424 (URN)63981 (Local ID)63981 (Archive number)63981 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2014-10-08
Enander, K., Aili, D., Baltzer, L., Lundström, I. & Liedberg, B. (2005). Alpha-helix-inducing dimerization of synthetic polypeptide scaffolds on gold. Langmuir, 21(6), 2480-2487
Open this publication in new window or tab >>Alpha-helix-inducing dimerization of synthetic polypeptide scaffolds on gold
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2005 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, no 6, p. 2480-2487Article in journal (Refereed) Published
Abstract [en]

Designed, synthetic polypeptides that assemble into four-helix bundles upon dimerization in solution were studied with respect to folding on planar gold surfaces. A model system with controllable dimerization properties was employed, consisting of negatively and positively charged peptides. Circular dichroism spectroscopy and surface plasmon resonance based measurements showed that at neutral pH, the peptides were able to form heterodimers in solution, but unfavorable electrostatic interactions prevented the formation of homodimers. The dimerization propensity was found to be both pH- and buffer-dependent. A series of infrared absorption−reflection spectroscopy experiments of the polypeptides attached to planar gold surfaces revealed that if the negatively charged peptide was immobilized from a loading solution where it was folded, its structure was retained on the surface provided it had a cysteine residue available for anchoring to gold. If it was immobilized as random coil, it remained unstructured on the surface but was able to fold through heterodimerization if subsequently exposed to a positively charged polypeptide. When the positively charged peptide was immobilized as random coil, heterodimerization could not be induced, probably because of high-affinity interactions between the charged primary amine groups and the gold surface. These observations are intended to pave the way for future engineering of functional surfaces based on polypeptide scaffolds where folding is known to be crucial for function.

Place, publisher, year, edition, pages
ACS Publications, 2005
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:liu:diva-15115 (URN)10.1021/la048029u (DOI)
Available from: 2008-10-16 Created: 2008-10-16 Last updated: 2018-01-12Bibliographically approved
Hederos (Håkansson), S. & Baltzer, L. (2005). Nucleophile Selectivity in the Acyl Transfer Reaction of a Designed Enzyme. Biopolymers, 79(6), 292-299
Open this publication in new window or tab >>Nucleophile Selectivity in the Acyl Transfer Reaction of a Designed Enzyme
2005 (English)In: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 79, no 6, p. 292-299Article in journal (Refereed) Published
Abstract [en]

The acyl transfer reaction of S-glutathionyl benzoate (GSB) is catalyzed by a rationally designed mutant of human glutathione transferase A1-1, A216H. The catalyzed reaction proceeds via the formation of an acyl intermediate and has been studied in the presence of nitrogen, oxygen, and sulfur nucleophiles to determine the selectivity with regards to nucleophile structure. Methanol was previously shown to react with the acyl intermediate and form the corresponding ester, methylbenzoate, under a significant rate enhancement. In the present investigation, the dependence on nucleophile structure and reactivity has been investigated. Ethane thiol gave rise to a larger rate enhancement in the enzyme-catalyzed reaction than ethanol, whereas ethylamine did not increase the reaction rate. The reactivities toward the acyl intermediate of primary and secondary alcohols with similar pKa values depended on the structure of the aliphatic chain, and 1-propanol was the most efficient alcohol. The reactivity of the oxygen nucleophiles was also found to depend strongly on pKa as 2,2,2-trifluoroethanol, with a pKa of 12.4, was the most efficient nucleophile of all that were tested. Saturation kinetics was observed in the case of 1-propanol, indicating a second binding site in the active site of A216H. The nucleophile selectivity of A216H provides the knowledge base needed for the further reengineering of A216H towards alternative substrate specificities.

Place, publisher, year, edition, pages
John Wiley & Sons, 2005
Keywords
acyl transfer, enzyme catalysis, glutathione transferase, protein design, selectivity
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-13366 (URN)10.1002/bip.20351 (DOI)
Available from: 2005-09-23 Created: 2005-09-23 Last updated: 2018-05-28
Andersson, T., Lundqvist, M., Dolphin, G. T., Enander, K., Jonsson, B.-H., Nilsson, J. W. & Baltzer, L. (2005). The binding of human Carbonic Anhydrase II by functionalized folded polypeptide receptors. Chemistry and Biology, 12(11), 1245-1252
Open this publication in new window or tab >>The binding of human Carbonic Anhydrase II by functionalized folded polypeptide receptors
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2005 (English)In: Chemistry and Biology, ISSN 1074-5521, E-ISSN 1879-1301, Vol. 12, no 11, p. 1245-1252Article in journal (Refereed) Published
Abstract [en]

Several receptors for human carbonic anhydrase II (HCAII) have been prepared by covalently attaching benzenesulfonamide carboxylates via aliphatic aminocarboxylic acid spacers of variable length to the side chain of a lysine residue in a designed 42 residue helix-loop-helix motif. The sulfonamide group binds to the active site zinc ion of human carbonic anhydrase II located in a 15 Å deep cleft. The dissociation constants of the receptor-HCAII complexes were found to be in the range from low micromolar to better than 20 nM, with the lowest affinities found for spacers with less than five methylene groups and the highest affinity found for the spacer with seven methylene groups. The results suggest that the binding is a cooperative event in which both the sulfonamide residue and the helix-loop-helix motif contribute to the overall affinity.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-13359 (URN)10.1016/j.chembiol.2005.08.018 (DOI)
Available from: 2005-09-21 Created: 2005-09-21 Last updated: 2017-12-13
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