Antimicrobial peptide

Antimicrobial resistance is an emerging challenge for health personnel and researchers. In such scenario, alternative strategies targeting novel ways to kill or inhibit growth of microbes are need of the hour. Antimicrobial peptide can be a promising candidate to deal with this crisis. Extracellular matrix protein vitronectin (Vn) is recently being established as a bactericidal agent against certain microbes. Caprine Vn has got few structural alterations as compare to human Vn.

7p nguaconbaynhay5 16-05-2020 16 2   Download

Tôm biển có hệ miễn dịch rất đặc biệt. Ngoài miễn dịch tế bào với sự tham gia của tế bào bạch cầu với hai quá trình cơ bàn là melanin hóa (melanization) và thực bào (phagocytosis). Trong cơ thể tôm còn có các peptid (AMPs-antimicrobial peptides) có khả năng tiêu diệt vật lạ/mầm bệnh xâm nhập. Đây được xem là phản ứng miễn dịch đầu tiên nhất chống lại khi mầm bênh xâm nhập.

4p chuteu_1 25-06-2013 107 9   Download

Division of Medicinal and Natural Products Chemistry, Department of Chemistry and Department of Chemical Engineering, University of Iowa, USA; 2Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark Synthetic peptides based on amino-acid residues 27–38 of human serum amyloid P component represent a novel type of heparin binders as they do not contain clusters of basic amino acids or other known features associated with protein or peptide heparin binding.

8p system191 01-06-2013 54 4   Download

Penaeidins are a family of antimicrobial peptides constitutively produced and stored in the haemocytes of penaeid shrimp. In response to microbial stimulation, they are released into the blood circulation and they further attach to shrimp cuticle surfaces through a chitin-binding property. In the present paper, we have analysed their expression, regulation and distribution in shrimp tissues in response to experimental microbial challenge.

12p system191 01-06-2013 41 6   Download

Mice expressing a C-terminal fragment of the prion protein instead of wild-type prion protein die from massive neuronal degeneration within weeks of birth. The C-terminal region of PrPc (PrP121–231) expressed in these mice has an intrinsic neurotoxicity to cultured neurones. Unlike PrPSc, which is not neurotoxic to neurones lacking PrPc expression, PrP121–231 was more neurotoxic to PrPc-deficient cells. Human mutations E200K and F198S were found to enhance toxicity of PrP121–231 to PrP-knockout neurones and E200K enhanced toxicity to wild-type neurones.

10p system191 01-06-2013 31 4   Download

The decoy approach against nuclear factor kB (NF-kB) is a useful tool to alter NF-kB dependent gene expression using synthetic oligonucleotides (ODNs) carrying NF-kB specific cis-elements. Unfortunately, ODNs are not stable and need to be extensively modified to be used in vivo or ex vivo. We have previously evaluated the possible use of peptide nucleic acids (PNAs) as decoy molecules. The backbone of PNAs is composed of N-(2-aminoethyl)glycine units, rendering these molecules resistant to both nucleases and proteases.

10p system191 01-06-2013 43 4   Download

The calcineurin (CaN) a and b catalytic subunit isoforms are coexpressed within almost all cell types. The enzymatic properties of CaN heterodimers comprised of the regulatory B subunit (CnB) with either the a or b catalytic subunit were compared using in vitro phosphatase assays. CaN containing the a isoform (CnAa) has lower Km and higher Vmax values than CaN containing the b isoform (CnAb) toward the PO4RII, PO4-DARPP-32(20–38) peptides, and p-nitrophenylphosphate (pNPP).

9p research12 01-06-2013 28 3   Download

In this review, we summarize recent progress in studying three main classes of prenyltransferases: (a) isoprenyl pyrophosphate synthases (IPPSs), which catalyze chain elongation of allylic pyrophosphate substrates via consecutive condensation reactions with isopentenyl pyrophosphate (IPP) to generate linear polymers with defined chain lengths; (b) protein prenyltransferases, which catalyze the transfer of an isoprenyl pyrophosphate (e.g. farnesyl pyrophosphate) to a protein or a peptide; (c) prenyltransferases, which catalyze the cyclization of isoprenyl pyrophosphates.

16p research12 01-06-2013 50 4   Download

We report the isolation of a novel antimicrobial peptide, bass hepcidin, from the gill of hybrid striped bass, white bass (Morone chrysops) · striped bass (M. saxatilis). After the intraperitoneal injection of Micrococcus luteus and Escherichia coli, the peptide was purified from HPLC fractions with antimicrobial activity against Escherichia coli. Sequencing by Edman degradation revealed a 21-residue peptide (GCRFCCNCCPNMSGCGVCCRF) with eight putative cysteines.

6p research12 01-06-2013 30 5   Download

A comparative study of thermodynamic and kinetic aspects of Cu(II) and Ni(II) binding at the N-terminal binding site of human and bovine serum albumins (HSA and BSA, respectively) and short peptide analogues was performed using potentiometry and spectroscopic techniques. It was found that while qualitative aspects of interaction (spectra and structures of complexes, order of reactions) could be reproduced, the quantitative parameters (stability and rate constants) could not.

9p research12 01-06-2013 38 4   Download

Gomesin is the first peptide isolated from spider exhibiting antimicrobial activities. This highly cationic peptide is composed of 18 amino-acid residues including four cysteines forming two disulfide linkages. The solution structure of gomesin has been determined using proton two-dimensional NMR (2D-NMR) and restrained molecular dynamics calculations. The global fold of gomesin consists in a wellresolved two-stranded antiparallel b sheet connected by a noncanonical b turn.

9p research12 01-06-2013 39 3   Download

The CD spectra of SMAP-29, an antimicrobial peptide from sheep, showed disordered structure in aqueous buffers, and significant helicity in membrane-like environments, including SDS micelles, lipopolysaccharide (LPS) dispersions, and trifluoroethanol buffer systems. A structure determined by NMR in 40% perdeuterated trifluoroethanol indicated that residues 8–17 were helical, residues 18–19 formed a hinge, and residues 20–28 formed an ordered, hydrophobic segment.

9p research12 01-06-2013 36 4   Download

Dendrimeric peptides selective for microbial surfaces have been developed to achieve broad antimicrobial activity and low hemolytic activity to human erythrocytes. The dendrimeric core is an asymmetric lysine branching tethered with two to eight copies of a tetrapeptide (R4) or an octapeptide (R8). The R4 tetrapeptide (RLYR) contains a putative microbial surface recognition BHHB motif (B ¼ basic, H ¼ hydrophobic amino acid) found in protegrins and tachyplesins whereas the octapeptide R8 (RLYRKVYG) consists of an R4 and a degenerated R4 repeat....

10p research12 01-06-2013 40 6   Download

Nourseothricins (syn. Streptothricins), agroupof nucleoside peptides produced by several streptomycete strains, contain a polyb-lysine chain of variable length attached in amide linkage to the amino sugar moiety gulosamine of the nucleoside portion. We show that the nourseothricin-pro-ducingStreptomyces nourseicontains an enzyme (NpsA) of an apparentMr56 000 that speci®cally activatesb-lysine by adenylation but does not bind to it as a thioester.

11p research12 29-04-2013 24 4   Download

Gaegurin 4 (GGN4), a 37-residue antimicrobial peptide, consists of two amphipathic ahelices (residues 2–10and 16–32) connected by a flexible loop region (residues 11– 15). As part of an effort to develop new peptide antibiotics with low molecular mass, the activities of C-terminally truncated GGN4 analogues were tested. D 24)37 GGN4, a peptide analogue with 14 residues truncated from the C-terminus of GGN4, showed a complete loss of anti-microbial activity.

8p research12 23-04-2013 31 2   Download

We report the recombinant neurolysin and thimet oligo-peptidase (TOP) hydrolytic activities towards internally quenched fluorescent peptides derived from the peptide Abz-GGFLRRXQ-EDDnp (Abz,ortho-aminobenzoicacid; EDDnp,N-(2,4-dinitrophenyl) ethylenediamine), in which X was substituted by 11 different natural amino acids. Neurolysin hydrolyzed these peptides at R–R or at R–X bonds, and TOP hydrolyzed at R–R or L–R bonds, showing a preference to cleave at three or four amino acids from the C-terminal end. ...

9p research12 23-04-2013 44 3   Download

The interactionofmany lytic cationic antimicrobial peptides with their target cells involves electrostatic interactions, hydrophobic effects, and the formation of amphipathic sec-ondary structures, such asahelices orbsheets. We have shown in previous studies that incorporating
30% D-aminoacids intoashortahelical lyticpeptidecomposedof leucine and lysine preserved the antimicrobial activity of the parent peptide, while the hemolytic activity was abolished.

12p research12 23-04-2013 35 2   Download

Pycnoporus cinnabarinuslaccaselac1genewasoverexpressed in Aspergillus niger, a well-known fungal host producing a large amount of homologous or heterologous enzymes for industrial applications. The corresponding cDNA was placed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter as a strong and constitutive pro-moter. The laccase signal peptide or the glucoamylase preprosequence ofA.

8p research12 23-04-2013 51 5   Download

Microcin J25 (MccJ25) is the single macrocyclic antimicro-bial peptidebelonging to the ribosomally synthesizedclass of microcins that are secreted byEnterobacteriaceae.Itshowed potent antibacterial activity against severalSalmonellaand Escherichiastrains and exhibited a compact three-dimen-sional structure [Blondet al. (2001) Eur. J. Biochem., 268, 2124–2133]. The molecular mechanisms involved in the biosynthesis, folding andmode of action of MccJ25 are still unknown.

11p tumor12 22-04-2013 44 2   Download

Wehave examined the effectsof three ring-sizeanalogsof the cyclicb-sheet antimicrobial peptidegramicidinS (GS) on the thermotropic phase behavior and permeability of phos-pholipid model membranes and on the growth of the cell wall-less Gram-positive bacteriaAcholeplasma laidlawiiB. These three analogs have ring sizes of 10 (GS10), 12 (GS12) or 14 (GS14) amino acids, respectively.

10p tumor12 22-04-2013 33 2   Download