摘要:

The ability of highly ordered tripeptide structures to keep or change their morphology in contact with organic vapors was studied. A thin film of tripeptidel‐leucyl‐l‐leucyl‐l‐leucine (LLL) was prepared having microcrystals and nanocrystals on its surface, which are stable upon vacuum drying but become objects of selective morphology change after a contact with vapors of organic solvents. Fine separate LLL crystals and their agglomerates of submicron and larger dimensions were observed by atomic force microscopy and scanning electron microscopy. After saturation with guest vapors, these crystals can remain intact or change their morphology with the increase in size or complete destruction depending on the guest molecular structure. The crystals completely lose their shape after the binding of pyridine vapors. The other studied guests produce much smaller transformations or have no effect on crystal morphology despite being sorbed by solid LLL, which was shown using quartz crystal microbalance sensor. The observed size‐exclusion effect for guest sorption by LLL was found to be broken by the same guests that can change the initial crystal shape. This helps to explain the morphology changes of LLL crystals after the guest sorption and release. Copyright © 2012 European Peptide Society and John Wil

ISSN:1075-2617    

DOI:10.1002/psc.1431

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

CIGB‐300 is a novel anticancer peptide that impairs the casein kinase 2‐mediated phosphorylation by direct binding to the conserved phosphoacceptor site on their substrates. Previous findings indicated that CIGB‐300 inhibits tumor cell proliferationin vitroand induces tumor growth delayin vivoin cancer animal models. Interestingly, we had previously demonstrated that the putative oncogene B23/nucleophosmin (NPM) is the major intracellular target for CIGB‐300 in a sensitive human lung cancer cell line. However, the ability of this peptide to target B23/NPM in cancer cells with differential CIGB‐300 response phenotype remained to be determined. Interestingly, in this work, we evidenced that CIGB‐300's antiproliferative activity on tumor cells strongly correlates with its nucleolar localization, the main subcellular localization of the previously identified B23/NPM target. Likewise, using CIGB‐300 equipotent doses (concentration that inhibits 50% of proliferation), we demonstrated that this peptide interacts and inhibits B23/NPM phosphorylation in different cancer cell lines as evidenced byin vivopull‐down and metabolic labeling experiments. Moreover, such inhibition was followed by a fast apoptosis on CIGB‐300‐treated cells and also an impairment of cell cycle progression mainly after 5 h of treatment. Altogether, our data not only validates B23/NPM as a main target for CIGB‐300 in cancer cells but also provides the first experimental clues to explain their differential antiproliferative response. Importantly, our findings suggest that further improvements to this cell penetrating peptide‐based drug should entail its more efficient intracellular delivery at such subcellular localization. Copyright © 2012 European Peptide Societ

ISSN:1075-2617    

DOI:10.1002/psc.1432

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

A novel avianβ‐defensin (AvBD), AvBD10, was discovered in the liver and bone marrow tissues from Chinese painted quail (Coturnix chinensis) in the present study. The complete nucleotide sequence of quail AvBD10 contains a 207‐bp open reading frame that encodes 68 amino acids. The quail AvBD10 was expressed widely in all the tissues from quails except the tongue, crop, breast muscle, and thymus and was highly expressed in the bone marrow. In contrast to the expression pattern of AvBD10 in tissues from quail, the chicken AvBD10 was expressed in all 21 tissues from the layer hens investigated, with a high level of expression in the kidney, lung, liver, bone marrow, and Harderian glands. Recombinant glutathione S‐transferase (GST)‐tagged AvBD10s of both quail and chicken were produced and purified by expression of the two cDNAs inEscherichia coli, respectively. In addition, peptide according to the respective AvBD10s sequence was synthesized, named synthetic AvBD10s. As expected, both recombinant GST‐tagged AvBD10s and synthetic AvBD10s of quail and chicken exhibited similar bactericidal properties against most bacteria, including Gram‐positive and Gram‐negative forms. However, no significant bactericidal activity was found for quail recombinant GST‐tagged AvBD10 againstSalmonella choleraesuisor for chicken recombinant GST‐tagged AvBD10 againstProteus mirabilis. Copyright © 2012 European Peptide Society and J

ISSN:1075-2617    

DOI:10.1002/psc.1437

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

Deposition of insoluble fibrillar aggregates of β‐amyloid (Aβ) peptides in the brain is a hallmark of Alzheimer's disease. Apart from forming fibrils, these peptides also exist as soluble aggregates. Fibrillar and a variety of nonfibrillar aggregates of Aβ have also been obtainedin vitro. Hexafluoroisopropanol (HFIP) has been widely used to dissolve Aβ and other amyloidogenic peptides. In this study, we show that the dissolution of Aβ40, 42, and 43 in HFIP followed by drying results in highly ordered aggregates. Although α‐helical conformation is observed, it is not stable for prolonged periods. Drying after prolonged incubation of Aβ40, 42, and 43 peptides in HFIP leads to structural transition from α‐helical to β‐conformation. The peptides form short fibrous aggregates that further assemble giving rise to highly ordered ring‐like structures. Aβ16–22, a highly amyloidogenic peptide stretch from Aβ, also formed very similar rings when dissolved in HFIP and dried. HFIP could not induce α‐helical conformation in Aβ16–22, and rings were obtained from freshly dissolved peptide. The rings formed by Aβ40, 42, 43, and Aβ16–22 are composed of the peptides in β‐conformation and cause enhancement in thioflavin T fluorescence, suggesting that the molecular architecture of these structures is amyloid‐like. Our results clearly indicate that dissolution of Aβ40, 42 and 43 and the amyloidogenic fragment Aβ16–22 in HFIP results in the formation of annular amyloid‐like structures. Copyright © 2012 Europ

ISSN:1075-2617    

DOI:10.1002/psc.2391

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

Histone deacetylase inhibitors (HDACIs) are a promising class of anticancer agents. To examine whether a slight change in the recognition domain could alter their inhibitory activity, we synthesized a series ofcyclo(−l‐Am7(S2Py)‐Aib‐l‐Phe(n‐Me)‐d‐Pro)derivatives and evaluated their HDAC inhibitory and anticancer activities. The peptides exhibited potent HDAC inhibitory activity and inhibited three human cancer cell lines with IC50in the micromolar range. Docking and molecular dynamics simulation were conducted to explore the interaction mechanisms of class I and II HDACs with these inhibitors. It revealed that the zinc ion in the active site coordinated five atoms of HDACs and the sulfur atom of the inhibitor. The metal binding domains of these compounds interacted with HDAC2, and the surface recognition domains of these compounds interacted with HDAC4 through hydrogen bonding. The hydrophobic interactions also provided favorable contributions to stabilize the complexes. The results obtained from this study would be helpful for us to design some novel cyclic tetrapeptides that may act as potent HDACIs. Copyright © 2012 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.2392

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

Colorectal cancers with metastatic potential secrete the glycoprotein carcinoembryonic antigen (CEA). CEA has been implicated in colorectal cancer metastasis by inducing Kupffer cells to produce inflammatory cytokines which, in turn, make the hepatic micro‐environment ideal for tumor cell implantation. CEA binds to the heterogeneous ribonucleoprotein M (hnRNP M) which acts as a cell surface receptor in Kupffer cells. The amino acid sequence in CEA, which binds the hnRNP M receptor, is Tyr‐Pro‐Glu‐Leu‐Pro‐Lys. In this study, the structure of Ac‐Tyr‐Pro‐Glu‐Leu‐Pro‐Lys‐NH2(YPELPK) was investigated using electronic circular dichroism, vibrational circular dichroism, and molecular dynamics simulations. The binding of the peptide to hnRNP M was also investigated using molecular docking calculations. The biological activity of YPELPK was studied using differentiated human THP‐1 cells, which express hnRNP M on their surface and secrete IL‐6 when stimulated by CEA. YPELPK forms a stable polyproline‐II helix and stimulates IL‐6 production of THP‐1 cells at micromolar concentrations. Copyright © 2012 European Pept

ISSN:1075-2617    

DOI:10.1002/psc.2393

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

An efficient method for the heteroconjugation of biomolecules carrying free amino groups was reported previously, where mixed polyfluorophenyl diesters of dicarboxylic acids with varied aliphatic chain length were shown to be efficient reagents for the conjugation of a variety of model biomolecules. The concept was based on the differential reactivity of the esters towards amines. The concept has now been further optimized, and a 2,6‐difluorophenyl‐pentafluorophenyl diester combination has been demonstrated to be the most efficient, both with respect to selectivity and to reaction rate. A pentafluorophenyl ester reacts faster with an amino group and requires a weaker base than a 2,6‐difluorophenyl ester that requires a stronger base and longer reaction time. With the use of this combination of esters, we obtained considerably shortened reaction times compared with those reported previously, yet still retaining the desired selectivity in heteroconjugation. The increased reactivity of the bifunctional reagent allowed the construction of sophisticated peptide heteroconjugates from peptides, carbohydrates and proteins, showing a wide scope of applicability in the field of assembling functional bioconjugates. Copyright © 2012 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/psc.2394

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

The emergence of strains of multidrug‐resistant Gram‐negative bacteria mandates a search for new types of antimicrobial agents. Alyteserin‐2a (ILGKLLSTAAGLLSNL.NH2) is a cationic,α‐helical peptide, first isolated from skin secretions of the midwife toad,Alytes obstetricans, which displays relatively weak antimicrobial and haemolytic activities. Increasing the cationicity of alyteserin‐2a while maintaining amphipathicity by the substitution Gly11→ Lys enhanced the potency against both Gram‐negative and Gram‐positive bacteria by between fourfold and 16‐fold but concomitantly increased cytotoxic activity against human erythrocytes by sixfold (mean concentration of peptide producing 50% cell death; LC50 = 24 µm). Antimicrobial potency was increased further by the additional substitution Ser7→Lys, but the resulting analogue remained cytotoxic to erythrocytes (LC50 = 38 µm). However, the peptide containingd‐lysine at positions 7 and 11 showed high potency against a range of Gram‐negative bacteria, including multidrug‐resistant strains ofAcinetobacter baumanniiandStenotrophomonas maltophilia(minimum inhibitory concentration = 8 µm) but appreciably lower haemolytic activity (LC50 = 185 µm) and cytotoxicity against A549 human alveolar basal epithelial cells (LC50 = 65 µm). The analogue shows potential for treatment of nosocomial pulmonary infections caused by bacteria that have developed resistance to commonly used antibiotics. Cop

ISSN:1075-2617    

DOI:10.1002/psc.2397

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY

摘要:

N‐acetyl‐seryl‐aspartyl‐lysyl‐proline (AcSDKP) is a natural inhibitor of pluripotent hematopoietic stem cell proliferation and is normally found in human plasma. Because AcSDKP is hydrolyzed by theN‐terminal active site of angiotensin converting enzyme and partially eliminated in urine, its plasma level is a result of a complex balance between its production, hydrolysis by ACE, and renal elimination. In this study, we attempted to establish an enzyme immunoassay (EIA) for quantifying AcSDKP‐like immunoreactive substance (IS), which is applicable for monitoring plasma AcSDKP levels in healthy subjects and patients with chronic renal failure. Usingβ‐d‐galactosidase‐labeled Gly‐γAbu‐SDKP as a marker antigen, an anti‐rabbit IgG‐coated immunoplate as a bound/free separator and 4‐methylumbelliferyl‐β‐d‐galactopyranoside as a fluorogenic substrate, a highly sensitive and specific EIA was developed for the quantification of AcSDKP‐IS in human plasma. The lower limit of quantification was 0.32 fmol/well, and the sharp inhibition competitive EIA calibration curve obtained was linear between 8.0 and 513 fmol/ml. This EIA was so sensitive that only 10 µl plasma sample was required for a single assay. The coefficients of variation (reproducibility) for human plasma concentrations of 0.2 and 2.1 pmol/ml were 7.2 and 7.7%, respectively, for inter‐assay and 13.3 and 7.8% for intra‐assay comparisons. Plasma AcSDKP‐IS level was significantly higher in patients with chronic renal failure (0.92 ± 0.39 pmol/ml) compared with healthy subjects (0.29 ± 0.07 pmol/ml). These results suggest that our EIA may be useful to evaluate plasma AcSDKP level as a biomarker in various patient

ISSN:1075-2617    

DOI:10.1002/psc.2400

出版商:John Wiley&Sons, Ltd    

年代:2012

数据来源: WILEY