The five bromotryptophans

Bittner, Shmuel; Scherzer, Roni; Harlev, Eli

doi:10.1007/s00726-006-0441-8

Cited by 43 publications

(34 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The best characterized of these AMPs is styelin D, which possesses α-helical structure and is highly unusual in that it contains twelve post-translationally modified residues [77]. For example, the peptide contained multiple bromotryptophan residues, which are found in the AMPs of other marine organisms [218,219,220,221,222] and play an important role in the life of sea sponges and lower marine invertebrates [223]. Styelin D’s post-translationally modified residues enhanced the peptide’s membranolytic action at low pH but only against Gram-positive bacteria.…”

Section: An Overview Of Ph Dependent Peptides and Proteins With Anmentioning

confidence: 99%

pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

et al. 2016

View full text Add to dashboard Cite

Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations and hydrogel delivery systems. Nonetheless, many pH dependent AMPs and antimicrobial proteins have yet to be fully characterized and these molecules, as a whole, represent an untapped source of novel biologically active agents that could aid fulfillment of the urgent need for alternatives to conventional antibiotics, helping to avert a return to the pre-antibiotic era.

show abstract

Section: An Overview Of Ph Dependent Peptides and Proteins With Anmentioning

confidence: 99%

pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

et al. 2016

View full text Add to dashboard Cite

show abstract

“…1, 2b), yielding a mixture of singly and doubly halogenated Tyr. For Trp the 2 position of the pyrrole ring and any position on the six-membered aromatic ring are targeted [39], analogous to naturally occurring Trp bromination patterns [40] (Figs. 1, 2a).…”

Section: Oxidation Agents and Reaction With Peptides And Proteinsmentioning

confidence: 99%

Oxidative protein labeling in mass-spectrometry-based proteomics

et al. 2010

View full text Add to dashboard Cite

Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label reactive functional groups in amino acids, primarily cysteine, methionine, tyrosine, and tryptophan. Nonspecific radical intermediates (reactive oxygen, nitrogen, or halogen species) can be produced by chemical, photochemical, electrochemical, or enzymatic methods. More targeted oxidation can be achieved by chemical reagents but also by direct electrochemical oxidation, which opens the way to instrumental labeling methods. Oxidative labeling of amino acids in the context of liquid chromatography(LC)–mass spectrometry (MS) based proteomics allows for differential LC separation, improved MS ionization, and label-specific fragmentation and detection. Oxidation of proteins can create new reactive groups which are useful for secondary, more conventional derivatization reactions with, e.g., fluorescent labels. This review summarizes reactions of oxidizing agents with peptides and proteins, the corresponding methodologies and instrumentation, and the major, innovative applications of oxidative protein labeling described in selected literature from the last decade.

show abstract

“…A comprehensive review on the synthesis and applications of tryptophans brominated in the aromatic ring was published in 2007, and so these topics are not further discussed herein [72]. Chlorotryptophan residues are found in several medicinally important compounds, including the anticancer agents rebeccamycin and diazonamide A [73].…”

Section: Halogenated Tryptophansmentioning

confidence: 99%