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Proline-rich Peptides (proline-rich + peptide)
Selected AbstractsShuttling Gold Nanoparticles into Tumoral Cells with an Amphipathic Proline-Rich PeptideCHEMBIOCHEM, Issue 6 2009Sílvia Pujals Abstract Golden bullets: The amphipathic proline-rich cell-penetrating peptide sweet arrow peptide (SAP) is able to transport 12 nm gold nanoparticles efficiently into HeLa cells, as observed by three microscopy techniques: transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and transmission X-ray microscopy (TXM). Multiconjugation to such nanoparticles may provide a convenient method for unifying the key drug properties of high activity, capacity to home onto targets and delivery to therapeutic places of action. Cell-penetrating peptides (CPPs) are a potential tool for intracellular delivery of different kinds of cargoes. Because of their growing use in nanobiomedicine, both for diagnostics and for treatment, metal nanoparticles are an interesting cargo for CPPs. Here, gold nanoparticles (AuNps) and the amphipathic proline-rich peptide SAP have been used. Conjugation of the peptide onto the AuNps was achieved by addition of a cysteine to the SAP sequence for thiol chemisorption on gold, and the attachment was confirmed by visible spectroscopy, dynamic light scattering (DLS), ,-potential (ZP), stability towards ionic strength (as high as 1,M NaCl), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HR-TEM) coupled to electron energy loss spectroscopy (EELS). AuNp-C-SAP internalization in HeLa cells was observed by three different microscopy techniques,TEM, confocal laser scanning microscopy (CLSM) and transmission X-ray microscopy (TXM),and all of them have confirmed the effective intracellular delivery of AuNps by SAP. [source] Identification of crucial residues for the antibacterial activity of the proline-rich peptide, pyrrhocoricinFEBS JOURNAL, Issue 17 2002Goran Kragol Members of the proline-rich antibacterial peptide family, pyrrhocoricin, apidaecin and drosocin appear to kill responsive bacterial species by binding to the multihelical lid region of the bacterial DnaK protein. Pyrrhocoricin, the most potent among these peptides, is nontoxic to healthy mice, and can protect these animals from bacterial challenge. A structure,antibacterial activity study of pyrrhocoricin against Escherichia coli and Agrobacterium tumefaciens identified the N-terminal half, residues 2,10, the region responsible for inhibition of the ATPase activity, as the fragment that contains the active segment. While fluorescein-labeled versions of the native peptides entered E. coli cells, deletion of the C-terminal half of pyrrhocoricin significantly reduced the peptide's ability to enter bacterial or mammalian cells. These findings highlighted pyrrhocoricin's suitability for combating intracellular pathogens and raised the possibility that the proline-rich antibacterial peptides can deliver drug leads into mammalian cells. By observing strong relationships between the binding to a synthetic fragment of the target protein and antibacterial activities of pyrrhocoricin analogs modified at strategic positions, we further verified that DnaK was the bacterial target macromolecule. Inaddition, the antimicrobial activity spectrum of native pyrrhocoricin against 11 bacterial and fungal strains and the binding of labeled pyrrhocoricin to synthetic DnaK D-E helix fragments of the appropriate species could be correlated. Mutational analysis on a synthetic E. coli DnaK fragment identified a possible binding surface for pyrrhocoricin. [source] PR-39 coordinates changes in vascular smooth muscle cell adhesive strength and locomotion by modulating cell surface heparan sulfate,matrix interactionsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2001John H. Chon PR-39 is proline-rich peptide produced at sites of tissue injury. While the functional properties of this peptide have not been fully defined, PR-39 may be an important regulator of processes related to cell-matrix adhesion since it reportedly upregulates syndecan-4, which is a critical determinant of focal adhesion formation. The ability of PR-39 to modulate the adhesion and chemokinetic migration behavior of arterial smooth muscle cells (SMCs) in a fashion coordinated with syndecan-4 expression was investigated. Treatment of SMCs with PR-39 did not alter syndecan-1 mRNA, but did induce a two-fold increase in syndecan-4 mRNA (P,<,0.0001) and significantly enhanced cell surface expression of both syndecan-4 (P,<,0.01) and heparan sulfate (HS) (P,<,0.05). These observations were consistent with an observed increase in cell-matrix adhesive strength (P,<,0.05) and a reduction in cell speed (P,<,0.01) on fibronectin-coated substrates. Incubation of PR-39 treated cells with a soluble fibronectin derived heparin-binding peptide, as a competitive inhibitor of heparan sulfate/matrix interactions, abolished these effects. These data suggest that PR-39 mediated alterations of cell adhesion and motility may be related, in part, to the increased expression of heparan sulfate glycosaminoglycans (GAGs) that accompany the upregulation of cell surface syndecan-4. Futhermore, this investigation supports the notion that factors which control syndecan-4 expression may play an important role in regulating adhesion related cell processes. © 2001 Wiley-Liss, Inc. [source] Mass spectrometry strategies applied to the characterization of proline-rich peptides from secretory parotid granules of pig (Sus scrofa)JOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2008Chiara Fanali Abstract Basic proline-rich proteins (bPRPs) are a class of proteins widely present in saliva of humans and other mammals. They are synthesized as preproproteins and enzymatically cleaved into small peptides before secretion from the salivary glands. Recently, we characterized two proline-rich peptides (SP-A and SP-B) in parotid secretory granules of pig (Sus Scrofa) that are derived from three isoforms of a PRP proprotein (Swiss-Prot data bank: Q95JC9-1, Q95JC9-2 and Q95JC9-3). Together the coding regions for SP-A and SP-B, which are repeated many times, account for 52,70% of the coding regions of the PRP proproteins. This study was undertaken to identify peptides encoded by unassigned regions of the PRP proproteins. RP-HPLC-ESI-IT-MS analysis of enriched granule preparations from pig parotid glands by two different analytical strategies identified ten new proline-rich peptides derived from the three proproteins. Together with the coding regions for SP-A and SP-B already identified it was possible to assign 68,75% of the proproteins coding regions. The peptide sequences indicated a number of unusual proteolytic cleavage sites suggesting the presence of unknown proprotein convertases. [source] Detection of transient protein,protein interactions by bimolecular fluorescence complementation: The Abl-SH3 casePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 7 2007Montse Morell Abstract Protein,protein interactions are essential in most biological processes. Many proteomic approaches have succeeded in the identification of strong and obligatory interactions but the study of weak and transient protein,protein interactions is still a challenge. The aim of the present study was to test the ability of bimolecular fluorescence complementation to detect and discriminate in vivo weak intracellular protein interactions. As a test case, the interaction of the SH3 domain from the c-Abl tyrosine kinase with both natural and designed targets has been chosen. The reassociation of functional yellow fluorescent protein (YFP) from its fragments requires previous binding between the SH3 domain and its partners; but once this occurs, the complex is trapped, turning transient SH3 interactions into stable, easily detectable ones. The method is very sensitive and can be implemented for proteomic analysis of weak protein interactions using flow cytometry. The fluorescence emission is dependent on the strength of the interaction, in such a way that it can be used, at least qualitatively, to screen for best binding candidates among similar proline-rich peptides. In addition, it is illustrated how this method can be used to gain structural insights into particular c-Abl SH3 interactions. [source] Structure, modifications and ligand-binding properties of rat profilin 2aACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2009Teemu Haikarainen Profilins are key regulators of the actin microfilament system and in neuronal tissues the profilin 2a isoform is the most abundant and important profilin. The high-resolution crystal structure of rat profilin 2a has been determined in the absence of ligands. By comparing the structure with those of peptide-liganded profilin 2a and unliganded profilin 2b, it can be concluded that the binding site for proline-rich peptides is pre-organized. The C-terminus of profilin 2a is also well ordered in the absence of ligand peptide, in contrast to the 2b isoform which is generated by alternative splicing. Covalent modifications of four cysteine residues were also detected in profilin 2a, as well as a number of other modifications in profilin 2 from rat brain; such modifications could significantly affect the function of profilin. It was also shown that profilin 2a binds to the neuronal protein palladin, including a synthetic palladin peptide; peptides from another profilin ligand, dynamin 1, failed to interact with both profilin 1 and profilin 2a. These results allow a better understanding of the structure,function relationships and ligand binding of mammalian profilin 2a. [source] | ||||||||||