All major classes of protein chaperones, including DnaK (the Hsp70 eukaryotic equivalent) and GroEL (the Hsp60 eukaryotic equivalent) have been found in Escherichia coli. Molecular chaperones enhance the yields of correctly folded polypeptides by preventing aggregation and even by disaggregating certain protein aggregates. Previously, we identified the ClpX heat‐shock protein of E. coli because it enables the ClpP catalytic protease to degrade the bacteriophage lambda O replication protein. Here we report that ClpX alone possesses all the properties expected of a molecular chaperone protein. Specifically, it can protect the lambda O protein from heat‐induced aggregation, disaggregate preformed lambda O aggregates, and even promote efficient binding of lambda O to its DNA recognition sequence. A lambda O‐ClpX specific protein‐protein interaction can be detected either by a modified ELISA assay or through the stimulation of ClpX's weak ATPase activity by lambda O. Unlike the behaviour of the major DnaK and GroEL chaperones, ClpX requires the presence of ATP or its non‐hydrolysable analogue ATP‐gamma‐S for efficient interaction with other proteins including the protection of lambda O from aggregation. However, ClpX's ability to disaggregate lambda O aggregates requires hydrolysable ATP. We propose that the ClpX protein is a bona fide chaperone, whose biological role includes the maintenance of certain polypeptides in a form competent for proteolysis by the ClpP protease. Furthermore, our results suggest that the ClpX protein also performs typical chaperone protein functions independent of ClpP.
Background. Low-temperature techniques that prevent protein denaturation are being used to extract collagen from fish skin for cosmetic purposes. These extracts contain collagen with its triple helix structure preserved, as well as a number of other proteins. Objectives. The aim of the study was to investigate collagen extracts from the skin of silver carp for the presence of small-molecule peptides. Material and Methods. Liquid chromatography-mass spectrometry (HPLC-MS) was performed to analyze collagen extracts from silver carp skin for the presence of small-molecule peptides. Results. A large number of different peptides were detected in the silver carp skin collagen extracts analyzed. Among the smaller peptides, the most abundant were those of 7-29 aminoacids originating from the following proteins: collagen Iα1, collagen Iα2, collagen Iα3, collagen VIα3, decorin, lumican, histone H2A, histone H2B and histone H4. Conclusions. The study demonstrated that, in addition to high-molecular-weight collagen proteins, acidic collagen extracts acquired from the skin of silver carp at temperatures up to 16°C also contain considerable amounts of small 7-29 amino-acid peptides. The application of these peptides could therefore be expected to result in beneficial clinical effects in patients in need of reconstructive treatment (Adv Clin Exp Med 2016, 25, 2, 227-235).
ing to replace animal collagen with another type, e.g. fish collagen [1].Studies on extracellular matrix proteins, including collagen, elastin, laminin and proteoglycans (among others), have revealed that they participate in the regulation of key cellular processes such as cell migration, adhesion and differentiation, organogenesis, mitogenesis and apoptosis [2]. This regulation is mediated by signal peptides, so-called matrikines, produced after a partial proteolysis of the matrix components; this term was first proposed by Maquart to define peptides that For over 20 years collagen of animal origin has been one of the hopes for elaborating novel therapeutic strategies. Studies conducted on animal models have demonstrated that collagen-derived peptides can be beneficial in fighting cancer, accelerating wound healing, and repairing damaged neurons, among other applications. However, all these studies were conducted using animal collagen samples, most often originating from bovine or porcine skin. Currently, due to reported cases of bovine spongiform encephalopathy (BSE) and foot-and-mouth disease ( AbstractBackground. Studies conducted on human cell culture models have demonstrated that collagen-derived peptides can exert a beneficial effect in medicine. However, all these studies were conducted using animal collagen samples, most often originating from bovine or porcine skin. Currently attempts are being made to replace animal collagen with fish collagen. Objectives. The aim of the study was to compare the effect of silver carp skin-derived peptide extract on the transcriptional activities of human VEGF and hsp70.1 gene promoters inserted into the plasmids with secreted alkaline phosphatase as a reporter gene. Material and Methods. Changes in the activity of the promoters were investigated using a HEK293FT cell line transfected with pVEGF-SEAP or pHsp70-SEAP. The cells were cultured in dishes containing peptides separated using reverse-phase high performance liquid chromatography. Results. The study demonstrated that the silver carp skin-derived peptide extract exerts both an inhibitory effect on the VEGF gene promoter and activating effect on the hsp70.1 gene promoter. Higher biological activity was recorded in the case of a freshly prepared peptide extract compared to one stored at 4°C for three months. Conclusions. The silver carp skin-derived collagen peptides influence VEGF and hsp70.1 gene promoters' transcriptional activity (Adv Clin Exp Med 2016, 25, 3, 415-423).
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