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Antimicrobial Peptides
Guest Editor: Mariana S. Castro

Editorial Note from Editor-in-Chief Pp. 1-1
Ben M. Dunn
[Editorial In PDF]

Editorial Pp. 2-2
Mariana S. Castro
[Full text article]

Insect Antimicrobial Peptides: Structures, Properties and Gene Regulation Pp. 3-11
Philippe Bulet and Reto Stöcklin
[Abstract] [Full text article]

Plant Defense and Antimicrobial Peptides Pp. 11-16
Mariana S. Castro and Wagner Fontes
[Abstract] [Full text article]

Antimicrobial Peptides: Cooperative Approaches to Protection Pp. 19-25
Aleksander Patrzykat and Susan E. Douglas
[Abstract] [Full text article]

Are Oblique Orientated α-Helices Used by Antimicrobial Peptides for Membrane Invasion? Pp. 27-29
Sarah R. Dennison, Frederick Harris and David A. Phoenix
[Abstract] [Full text article]

Amphiphilic α-Helical Antimicrobial Peptides and Their Structure/Function Relationships Pp. 31-39
Sarah R. Dennison, James Wallace, Frederick Harris and David A. Phoenix
[Abstract] [Full text article]

Antimicrobial Peptide Microbicides Targeting HIV Pp. 41-47
Alexander M. Cole
[Abstract] [Full text article]

Immunocontinuum: Perspectives in Antimicrobial Peptide Mechanisms of Action and Resistance Pp.49-67
Nannette Y. Yount and Michael R. Yeaman
[Abstract] [Full text article]

General Articles

Purification and Properties of β-Alanine Synthase from Calf Liver Pp. 69-73
Gunter Waldmann, Paul F. Cook and Klaus D. Schnackerz
[Abstract] [Full text article]

Changes in Conformation of Human Neuronal Tau During Denaturation in Formaldehyde Solution Pp. 75-78
Chun-Lai Nie, Wei Zhang, Dai Zhang and Rong-Qiao He
[Abstract] [Full text article]

Atomic Force Microscopy Study of Human Amylin (20-29) Fibrils Pp. 79-83
Victoria L. Sedman, Stephanie Allen, Weng C. Chan, Martyn C. Davies, Clive J. Roberts, Saul J.B. Tendler and Philip M. Williams
[Abstract] [Full text article]

Production of Minichaperone (sht GroEL191-345) and Its Function in the Refolding of Recombinant Human Interferon Gamma Pp. 85-88
Yi-Xin Guan, Zheng-Zheng Fei, Man Luo, Shan-Jing Yao and Man-Gi Cho
[Abstract] [Full text article]

Hylins: Bombinins H Structurally Related Peptides from the Skin Secretion of the Brazilian Tree-Frog Hyla biobeba Pp. 89-93
Mariana S. Castro, Rubens H. Matsushita, Antonio Sebben, Marcelo V. Sousa and Wagner Fontes
[Abstract] [Full text article]

Novel Processing and Localization of catA, ccdA Associated Thiol-Disulfide Oxidoreductase, in Protein Hyper-Producing Bacterium Brevibacillus choshinensis Pp.95-98
Ryoichi Tanaka, Makoto Mizukami and Masao Tokunaga
[Abstract] [Full text article]

Abstracts

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Editorial Note from Editor-in-Chief
Ben M. Dunn
[Editorial In PDF]

The first issue of Volume 12 of Protein and Peptide Letters brings many changes to our journal following a very successful 2004. First, we are pleased to welcome Anna Maria Papini as the new Editor-for-Europe. Dr. Papini replaces Robin Leatherbarrow, who served with distinction from 1997 through 2004. We also want to acknowledge the outstanding contributions of John Wade, Editor-for-Asia & Australia. Authors in those parts of the world should submit their manuscripts to either Dr. Papini or Dr. Wade. We have also begun the construction of a special website, www.bentham-mps.org, for the electronic submission of manuscripts and assignment of referees. We expect this system to be operational during 2005 and will provide updates on the regular Bentham Science website, www.bentham.org. Second, we have expanded the Editorial Board to reflect the wide scope of topics covered in each issue. Names and affiliations are given in the masthead on the inside front cover. Authors are welcome to suggest a member of the Editorial Board to oversee the peer review of their manuscripts. Third, we plan to publish eight issues in Volume 12 for 2005, an increase of 25% in pages. The fourth major change is that we have switched the format of the articles in the journal to the two-column style, which permits publication of 40% more pages in each issue. This is necessary for two reasons: first, the two-column style has become the standard for other Bentham Science Publishing journals; second, the increasing flow of manuscripts submitted and accepted to the journal has created a demand for more space. In the future, authors can submit their manuscripts in a more simplified format and the accepted papers will be type-set for publication. We will continue the policy of sending PDF files as the page proofs for author approval before publication. A big reason for the move to the two column format has been the increase in the number of Hot Topic issues that have been organized by volunteer Guest Editors. Hot Topic issues provide cutting-edge reviews of a focused topic and are an excellent way to stimulate further research on a subject of current interest. Publishing a Hot Topic issue can, however, cause a delay in publishing regular individual manuscript; thus, another new development is our new policy of combining regular manuscripts with some Hot Topic issues. We welcome new suggestions for the Hot Topic issues and volunteers to organize them. Please send a proposal to the Editor-in-Chief at bdunn@ufl.edu. We will continue our policies of publishing stand-alone mini-reviews on all topics in protein and peptide science, regular submitted manuscripts, and Crystallization Reports in addition to the special Hot Topics issues. Finally, I want to thank all contributors to Protein and Peptide Letters, both authors and referees. It has been my pleasure to be associated with this journal and to work with so many authors, editors, and referees from around the world of science. We look forward to significant improvements in Protein and Peptide Letters in 2005. As always, I welcome reader input at any time.

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Editorial
Mariana S. Castro
[Editorial In PDF]

Antimicrobial peptides (AMPs) are ubiquitous molecules as they are found in microorganisms as well as in plants, invertebrates and also vertebrates. They represent the first line of defense against pathogens acting as effector molecules of innate immunity. The emergence of resistance to commonly used antibiotics has stimulated the search for new naturally occurring bactericidal and fungicidal agents that may have clinical utility. Nowadays databases contain more than 800 sequences of AMPs from different sources and many studies are in progress in order to evaluate the potential clinical applications of these peptides. This issue of Protein and Peptide Letters contains seven manuscripts which describe research on antimicrobial peptides, highlighting the amazing growth of this field during the last few years. In the opening article, Bulet and Stöcklin focus on the structures and biological properties of AMPs from insects. They also discuss the transduction signaling pathways controlling AMPs gene expression and explore the example of Drosophila that may discriminate between bacterial and fungal infections. In the second paper, Castro and Fontes present the events involved in plant defense and also describe the major groups of plant AMPs: thionins, plant defensins and lipid transfer proteins. The review by Patrzykat and Douglas summarizes the diversity of AMPs focusing on their biological activities against bacteria and in the host. Dennison et al. present the first systematic analysis of the presence of oblique oriented α-helices in AMPs that might be used in their antimicrobial action. In the next article, Dennison et al. thoroughly review the involvement of amphiphilic α-helical structure in the mechanisms of action of AMPs. They discuss potential mechanisms by which AMPs are able to induce the destabilization of biological membranes and the structural features (influence of amino acid composition, sequence length, molecular mass, pI) which are required for function. The review by Cole presents an interesting uptake on the development of topical microbicides for sexually transmitted diseases, with particular emphasis on q-defensins, protegrins, tachyplesins and polyphemusins as examples of minidefensins that might be used as templates for microbicide development. In the last manuscript, Yount and Yeaman describe the recent advances in the mechanisms of action of AMPs and in understanding pathogen resistance to antimicrobial peptides through constitutive or inducible mechanisms. Finally, I hope that readers enjoy this issue and that the concepts and information available here contribute to their own studies on this challenging area of peptide research.

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Insect Antimicrobial Peptides: Structures, Properties and Gene Regulation
Philippe Bulet and Reto Stöcklin
[Full text article]

Antimicrobial peptides (AMPs) are part of the armament that insects have developed to fight off pathogens. Insect AMPs are typically cationic and often made of less than 100 amino acid residues. Although their structures are diverse, most of the AMPs can be assigned to a limited number of families. The most common structures are represented by peptides assuming a α-helical conformation in organic solutions or disulfide-stabilized β-sheets with or without α- helical domains present. The diverse activity spectrum of these peptides may indicate different modes of action. Genetic analysis in the Drosophila model evidenced that multiple signal transduction pathways are activating the genes coding AMPs.

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Plant Defense and Antimicrobial Peptides
Mariana S. Castro and Wagner Fontes
[Full text article]

Plants are constantly exposed to a large array of pathogenic organisms and the survival in these conditions demands quick defense responses which include the synthesis of defense peptides and proteins with antimicrobial properties. The main groups of antimicrobial peptides found in plants are thionins, defensins and lipid transfer proteins. They constitute interesting candidates to engineer disease resistance in plants.

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Antimicrobial Peptides: Cooperative Approaches to Protection
Aleksander Patrzykat and Susan E. Douglas
[Full text article]

Reports of cationic antimicrobial peptides (CAPs) have become standard fare in research literature. But with several hundred peptides described to date, the investigator who tries to navigate the proposed models of their activity is only treated to a generous serving of incongruencies. Rather than acting in isolation as antimicrobial molecules, CAPs also may synergize with other molecules of innate immunity and modulate both innate and adaptive immune systems, thus providing a link between the various mechanisms that result in host protection.

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Are Oblique Orientated α-Helices Used by Antimicrobial Peptides for Membrane Invasion?
Sarah R. Dennison, Frederick Harris and David A. Phoenix
[Full text article]

Oblique orientated α-helices are highly specialised protein structural elements that penetrate membranes at a shallow angle and are used to promote membrane destabilisation by a number of protein classes. Here, the use of extended hydrophobic moment methodology shows that the amphibian extrudates, aurein 1.2 and citropin 1.1, may use oblique orientated α-helices in their antimicrobial action and that such use may be shared by other antimicrobial peptides. This appears to be the first systematic analysis of these peptides for the possession of oblique orientated α-helical structure.

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Amphiphilic α-Helical Antimicrobial Peptides and Their Structure/Function Relationships
Sarah R. Dennison, James Wallace, Frederick Harris and David A. Phoenix
[Full text article]

To facilitate microbial membrane invasion, amphiphilic α-helical antimicrobial peptides (α-AMPs) show a spatial segregation of hydrophobic and hydrophilic residues about the α-helical long axis. Here we discuss potential mechanisms by which these peptides are able to disrupt membrane structure and the structural characteristics, which are required for function.

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Antimicrobial Peptide Microbicides Targeting HIV
Alexander M. Cole
[Full text article]

Cationic antimicrobial peptides and proteins are among the earliest molecular effectors of the innate arm of immunity in humans and other vertebrates. This review, inspired by recent emphasis on the development of topical preventatives for sexually transmitted infections, describes antimicrobial peptides and proteins in the context of microbicide design and development. Particular emphasis is placed on the defensin family of peptides.

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Immunocontinuum: Perspectives in Antimicrobial Peptide Mechanisms of Action and Resistance
Nannette Y. Yount and Michael R. Yeaman
[Full text article]

Antimicrobial peptides are present in organisms spanning virtually every kingdom, and employ sophisticated mechanisms to exert rapid microbicidal action consistent with their key roles in host defense. Offsetting these mechanisms, some microbial pathogens have evolved complex countermeasures to neutralize exposure to and subvert mechanisms of antimicrobial peptides. The following discussion highlights recent advances that offer greater understanding of the mechanisms of action and resistance of antimicrobial peptides.

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Purification and Properties of β-Alanine Synthase from Calf Liver
Gunter Waldmann, Paul F. Cook and Klaus D. Schnackerz
[Full text article]

β-Alanine synthase (EC 3.5.1.6) catalyzes the conversion of N-carbamyl-β-alanine to β-alanine, ammonia and CO₂. The enzyme has been purified to apparent homogeneity from calf liver. The molecular size, pH optimum and substrate specificity have been determined. Sequence alignment of β-alanine synthases with N-carbamyl-D-amino acid amidohydrolase from Agrobacter sp. revealed the conservation of a catalytically important triad Glu-Lys-Cys, most likely involved in the breakdown of N-carbamyl-β-alanine.

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Changes in Conformation of Human Neuronal Tau During Denaturation in Formaldehyde Solution
Chun-Lai Nie, Wei Zhang, Dai Zhang and Rong-Qiao He
[Full text article]

Human neuronal tau was incubated in formaldehyde solution at low concentrations and the intensity of light scattering of tau-40 solution at 480 nm increased markedly. Then potassium iodide was used to quench the intrinsic fluorescence of tau. The fluorescent quenching constants decreased as formaldehyde concentrations increased. 8-anilino- 1-naphthalenesulfonic acid (ANS) binding assay showed that a putative hydrophobic core formed in tau polymers during incubation with formaldehyde. Native tau was hydrolyzed by immobilized earthworm fibrinolytic enzyme-II (EFE-II), producing a digested fragment (36-37 kDa). However, formaldehyde-treated tau could not be digested under the same conditions, suggesting that aggregated protein was relatively rigidly deposited.

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Atomic Force Microscopy Study of Human Amylin (20-29) Fibrils
Victoria L. Sedman, Stephanie Allen, Weng C. Chan, Martyn C. Davies, Clive J. Roberts, Saul J.B. Tendler and Philip M. Williams
[Full text article]

Here we present atomic force microscopy images of the fibrils formed by human amylin(20-29). This peptide is a fragment of the polypeptide amylin, the major proteinaceous component of amyloid deposits found in cases of type-II diabetes mellitus. Our results demonstrate that the amylin(20-29) peptide fragment forms amyloid-like fibrils that display polymorphic structures. Twisting along the axis of fibrils was often observed in fibrils aged for 6 hours but disappeared in mature fibrils aged for longer time periods.

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Production of Minichaperone (sht GroEL191-345) and Its Function in the Refolding of Recombinant Human Interferon Gamma
Yi-Xin Guan, Zheng-Zheng Fei, Man Luo, Shan-Jing Yao and Man-Gi Cho
[Full text article]

The recombinant minichaperone sht GroEL191-345 was cultivated in a 3.7 L stirred bioreactor with the high yield of 216.2 mg/L broth. In the refolding of recombinant human interferon gamma (rhuIFN-β) inclusion bodies, more than 2-3 fold enhancement in protein mass recovery and total activity were observed in the presence of free or immobilized minichaperone to the refolding buffer.

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Hylins: Bombinins H Structurally Related Peptides from the Skin Secretion of the Brazilian Tree-Frog Hyla biobeba
Mariana S. Castro, Rubens H. Matsushita, Antonio Sebben, Marcelo V. Sousa and Wagner Fontes
[Full text article]

Two hemolytic peptides were isolated from the skin secretion of the Brazilian Hylidae frog Hyla biobeba, using reversed-phase chromatographic procedures. Hylins b1 and b2 exhibit short linear polypeptide chains, a large number of hydrophobic residues, amidated C-termini and hemolytic properties. These two novel peptides are the first examples of bombinins H-like peptides isolated from anurans species not related to Bombina species.

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Novel Processing and Localization of catA, ccdA Associated Thiol-Disulfide Oxidoreductase, in Protein Hyper-Producing Bacterium Brevibacillus choshinensis
Ryoichi Tanaka, Makoto Mizukami and Masao Tokunaga
[Full text article]

Previously, we have cloned ccdA and its associated thiol-disulfide oxidoreductase gene, catA, in Brevibacillus choshinensis. CcdA is known to be an integral membrane protein and its associated oxidoreductase homologues are believed to be membrane anchoring proteins, both providing reducing equivalents across the membrane to control correct disulfide bond formation. Here, we found that CatA is first localized as a membrane bound form and then slowly released into the cellular periphery and culture medium with cleavage at a novel processing site.