Hemolytic Protein Research Articles

Study of the Salivary Glands in Triatominae (Hemiptera, Reduviidae, Triatominae): Their Color and Application to the Chagas Disease Vector Evolution.

Chagas disease is caused by Trypanosoma cruzi and transmitted by feces of a triatomine that has the habit of defecating during blood feeding. The salivary glands of triatomines are important to hematophagy because their saliva is rich in anticoagulant and hemolytic proteins. The salivary glands of some Rhodnius species analyzed are reddish due to the presence of nitrophorins (antihemostatic activity). The present study aimed to analyze the color pattern of the salivary glands of 67 triatomine species to evaluate whether the presence of nitrophorins is a synapomorphy of Rhodnius or the tribe Rhodniini, or if it is shared with triatomines of the tribes Triatomini and Cavernicolini. Since only the species of the tribe Rhoniini present red glands, it is admitted that the presence of nitrophorin proteins is a synapomorphy of the tribe Rhodniini and that this tribe has derived more recently when compared with Triatomini and Cavernicolini.

Testing of antiviral characteristics of flammutoxin in transgenic tobacco

Flammutoxin (FTX), a protein from fruiting bodies of edible mushroom Flammulina velutipes, is a hemolytic pore-forming protein and a transepithelial electrical resistance-decreasing protein. FTX also acts as an antiviral protein to inhibit Tobacco mosaic virus (TMV) infection of tobacco plants. To clarify its inhibition mechanism for TMV, the following experiments were performed. The gene FTX was introduced into the vector pBinFTX and then transformed into tobacco plants using Agrobacterium tumefaciens. The transgenic tobacco plant expressing FTX showed antiviral activities, and the development of TMV in tobacco was retarded after inoculated with TMV. Not only was the appearance of mosaic symptoms postponed, but also systemic symptoms were lessened in transgenic tobacco plants than in wild-type controls. The results indicate that FTX has antiviral activities.

Relationship between intracellular calcium and morphologic changes in rabbit erythrocytes: Effects of the acylated and unacylated forms of E. coli alpha-hemolysin

Alpha-hemolysin (HlyA) is a hemolytic and cytotoxic protein secreted by uropathogenic Escherichia coli strains, whose expression correlates with the severity of the infections produced. HlyA is synthesized as a protoxin, ProHlyA, that becomes matured to the active form in the cytosol by hemolysin-C–directed fatty acylation at the ε-amino residues of Lys 564 and Lys 690, before export from the toxin-producing bacteria. This posttranslational modification is remarkable because the nature of the protein is changed by the lipidic moiety from a benign protein to a frank toxin.In the present work, we demonstrated for the first time that, despite being hemolitically inactive, ProHlyA induced cellular morphologic changes in rabbit erythrocytes. A discocyte-to-echinocyte transformation was triggered by the protoxin in the absence of any accompanying increase in intracellular-Ca2+ levels. In addition, the Ca2+-influx kinetics in HlyA-treated erythrocytes indicated that the active toxin induced an elevation in intraerythrocyte-Ca2+ content in a biphasic manner, with an initial rise in Ca2+ that depended on the association of the protein with the target membrane and a second increment corresponding to an activation of purinergic channels. The first increase was sufficient to trigger a discocyte-echinocyte-spherocyte transition in erythrocyte shape, though the subsequent rise mediated by purinergic signalling was essential for the occurrence of hemolysis. The results presented here provide new insights into the mechanism of action of this toxin.

Continuous-Flow Electrokinetic-Assisted Plasmapheresis by Using Three-Dimensional Microelectrodes Featuring Sidewall Undercuts.

We present a novel plasmapheresis device designed for a fully integrated point-of-care blood analysis microsystem. In the device, fluidic microchannels exhibit a characteristic cross-sectional profile arising from distinct three-dimensional (3D) microelectrodes featuring sidewall undercuts readily integrated through a single-mask process. The structure leverages mainly electrothermal convective rolls that efficiently manifest themselves in physiological fluids and yet have received inadequate attention for the application of plasmapheresis due to concerns over Joule heating. Using this device, we show that such convective rolls not only lead to plasma extraction at a high yield and purity but also deliver plasma at an acceptable quality with no evidence of hemolytic stress or protein denaturation. Specifically, plasma from 1.5 μL of whole blood diluted to 4% hematocrit in a high-conductivity buffer (1.5 S/m) is extracted in a continuous flow at a fraction of 70% by using a peak voltage of ±10 Vp applied at 650 kHz; the extracted plasma is nearly 99% pure, as shown by a rigorous assessment using flow cytometry. The plasmas obtained using this device and using conventional centrifugation and sedimentation are of comparable quality as revealed by absorbance and circular dichroism spectra despite thermal gradients; however, these gradients effectively drive electrothermal bulk flows, as assessed using the microparticle image velocity technique. The device achieves high target molecule recovery efficiency, delivering about 97% of the proteins detected in the plasma obtained using sedimentation. The utility of the extracted plasma is further validated based on the detection of prostate-specific antigen at clinically relevant levels.

Bidirectional Transformation of a Metamorphic Protein between the Water-Soluble and Transmembrane Native States.

The bidirectional transformation of a protein between its native water-soluble and integral transmembrane conformations is demonstrated for FraC, a hemolytic protein of the family of pore-forming toxins. In the presence of biological membranes, the water-soluble conformation of FraC undergoes a remarkable structural reorganization generating cytolytic transmembrane nanopores conducive to cell death. So far, the reverse transformation from the native transmembrane conformation to the native water-soluble conformation has not been reported. We describe the use of detergents with different physicochemical properties to achieve the spontaneous conversion of transmembrane pores of FraC back into the initial water-soluble state. Thermodynamic and kinetic stability data suggest that specific detergents cause an asymmetric change in the energy landscape of the protein, allowing the bidirectional transformation of a membrane protein.

Effect of photografting 2-hydroxyethyl acrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats

Poly(ethylene-co-vinyl alcohol) (EVAL) has been recommended as a material suitable for blood contacting applications. Effect of ethylene content and associated hydrophobicity of EVAL on the blood–material interactions have been documented in the literature. In this work, surface chemistry of EVAL substrate was altered by photografting a hydrophilic monomer, 2-hydroxyethyl acrylate (HEA) with the aid of a photoinitiator, benzophenone (BP), and the effect of surface modification on the blood–material interactions was investigated. Since the modified material was intended to be used as leukodepletion filters, a solution containing EVAL, HEA and BP was electrospun into fibroporous mats and UV treated to induce grafting. Degree of grafting, bonding between fibers and fiber diameter increased with increase in UV exposure time whereas mechanical properties showed a decreasing trend. Decreased water contact angle indicated improved wetting characteristics. In vitro hemocompatibility tests revealed that the modified EVAL surface exhibited significantly lower hemolytic activity, protein adsorption and platelet adhesion than neat EVAL. The modification did not have any substantial effect on the activation of the complement system and coagulation parameters. Photografting led to significant reduction in the adhesion of red blood cells (RBC) whereas white blood cell (WBC) consumption remained above 90%. The results implied that photografting HEA on EVAL substantially improves hemocompatibility of EVAL and when it is used as a filter, it selectively removes leukocytes and allows easy passage of other blood components.

Dynamics of the Immune Response of the Horse MusselModiolus kurilensis(Bernard, 1983) Following Challenge with Heat-Inactivated Bacteria

ABSTRACT Alterations of the cell-mediated and humoral immune parameters were revealed in the bivalves Modiolus kurilensis from the Sea of Japan after injection with heat-inactivated Staphylococcus aureus. Preliminary screening of the in vitro phagocytic activity (PA) and hemagglutination (HA) enabled to obtain homogeneous groups of individuals for all of the parameters to be measured. Changes in hemolymph parameters were studied over a 14-day period. High values for hemolytic activity (HL) and protein concentration (PC) persisted until 36 h, with high levels of HA persisting until 168 h. The in vitro PA level was low from 3 to 6 h postchallenge, which was caused active in vivo hemocyte elimination of the injected antigen in the first 12 h. A significant increase in the in vitro PA up to 36 h was related to a rise in the circulating total hemocyte concentration (from 6 to 12 h) and to in vivo S. aureus clearance (in the first 48 h). For the first time, a complex correlation analysis of the interplay betwee...

A Pore-Forming Toxin Requires a Specific Residue for Its Activity in Membranes with Particular Physicochemical Properties

The physicochemical landscape of the bilayer modulates membrane protein function. Actinoporins are a family of potent hemolytic proteins from sea anemones acting at the membrane level. This family of cytolysins preferentially binds to target membranes containing sphingomyelin, where they form lytic pores giving rise to cell death. Although the cytolytic activity of the actinoporin fragaceatoxin C (FraC) is sensitive to vesicles made of various lipid compositions, it is far from clear how this toxin adjusts its mechanism of action to a broad range of physiochemical landscapes. Herein, we show that the conserved residue Phe-16 of FraC is critical for pore formation in cholesterol-rich membranes such as those of red blood cells. The interaction of a panel of muteins of Phe-16 with model membranes composed of raft-like lipid domains is inactivated in cholesterol-rich membranes but not in cholesterol-depleted membranes. These results indicate that actinoporins recognize different membrane environments, resulting in a wider repertoire of susceptible target membranes (and preys) for sea anemones. In addition, this study has unveiled promising candidates for the development of protein-based biosensors highly sensitive to the concentration of cholesterol within the membrane.

Structural basis for self-assembly of a cytolytic pore lined by protein and lipid.

Pore-forming toxins (PFT) are water-soluble proteins that possess the remarkable ability to self-assemble on the membrane of target cells, where they form pores causing cell damage. Here, we elucidate the mechanism of action of the haemolytic protein fragaceatoxin C (FraC), a α-barrel PFT, by determining the crystal structures of FraC at four different stages of the lytic mechanism, namely the water-soluble state, the monomeric lipid-bound form, an assembly intermediate and the fully assembled transmembrane pore. The structure of the transmembrane pore exhibits a unique architecture composed of both protein and lipids, with some of the lipids lining the pore wall, acting as assembly cofactors. The pore also exhibits lateral fenestrations that expose the hydrophobic core of the membrane to the aqueous environment. The incorporation of lipids from the target membrane within the structure of the pore provides a membrane-specific trigger for the activation of a haemolytic toxin.

Hemolytic activity of dermatophytes species isolated from clinical specimens

Hemolytic activity was recently reported for several pathogenic fungal species, such as Aspergillus, Candida, Trichophyton, Penicillium and Fusarium. Based on a number of mechanistic and characterization studies, several fungal hemolysins have been proposed as virulence factors. Hemolysins lyse red blood cells resulting in the release of iron, an important growth factor for microbes especially during infection. The requirement of iron in fungal growth is necessary for metabolic processes and as a catalyst for various biochemical processes. Expression of a hemolytic protein with capabilities to lyse red blood cells has also been suggested to provide a survival strategy for fungi during opportunistic infections. The aims of this study were to investigate the hemolytic activities of dermatophytes species isolated from patients with dermatophytosis. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on Mycobiotic agar and Sabouraud's dextrose agar. To determine hemolytic activities of dermatophytes species, they were subcultured on Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. In this study, 66 dermatophytes strains were isolated from clinical specimens and were identified by six different species: 43 (65.1%) Trichophyton rubrum, 7 (10.7%) Trichophyton mentagrophytes, 5 (7.6%) Microsporum canis, 5 (7.6%) Trichophyton tonsurans, 4 (6.0%) Epidermophyton floccosum and 2 (3.0%) Trichophyton violaceum. Twenty-one T. rubrum strains showed incomplete (alpha) hemolysis and nine T. rubrum strains showed complete (beta) hemolysis, whereas hemolysis was absent in 13 T. rubrum strains. Four T. mentagrophytes strains showed complete hemolysis and three T. tonsurans strains showed incomplete hemolysis. However, M. canis, E. floccosum and T. violaceum species had no hemolytic activity. Hemolytic activity is pronounced in dermatophytes and may play an important role as a virulence factor. Hemolysins produced may play an important role in the balance between the host's cellular immunity and the ability of the fungus to diminish the immune response.

Characteristics of hemolytic activity induced by the aqueous extract of the Mexican fire coral Millepora complanata.

BackgroundMillepora complanata is a plate-like fire coral common throughout the Caribbean. Contact with this species usually provokes burning pain, erythema and urticariform lesions. Our previous study suggested that the aqueous extract of M. complanata contains non-protein hemolysins that are soluble in water and ethanol. In general, the local damage induced by cnidarian venoms has been associated with hemolysins. The characterization of the effects of these components is important for the understanding of the defense mechanisms of fire corals. In addition, this information could lead to better care for victims of envenomation accidents.MethodsAn ethanolic extract from the lyophilized aqueous extract was prepared and its hemolytic activity was compared with the hemolysis induced by the denatured aqueous extract. Based on the finding that ethanol failed to induce nematocyst discharge, ethanolic extracts were prepared from artificially bleached and normal M. complanata fragments and their hemolytic activity was tested in order to obtain information about the source of the heat-stable hemolysins.ResultsRodent erythrocytes were more susceptible to the aqueous extract than chicken and human erythrocytes. Hemolytic activity started at ten minutes of incubation and was relatively stable within the range of 28-50°C. When the aqueous extract was preincubated at temperatures over 60°C, hemolytic activity was significantly reduced. The denatured extract induced a slow hemolytic activity (HU50 = 1,050.00 ± 45.85 μg/mL), detectable four hours after incubation, which was similar to that induced by the ethanolic extract prepared from the aqueous extract (HU50 = 1,167.00 ± 54.95 μg/mL). No significant differences were observed between hemolysis induced by ethanolic extracts from bleached and normal fragments, although both activities were more potent than hemolysis induced by the denatured extract.ConclusionsThe results showed that the aqueous extract of M. complanata possesses one or more powerful heat-labile hemolytic proteins that are slightly more resistant to temperature than jellyfish venoms. This extract also contains slow thermostable hemolysins highly soluble in ethanol that are probably derived from the body tissues of the hydrozoan.

Purification and characterization of a novel C-type hemolytic lectin for clot lysis from the fresh water clam Villorita cyprinoides: A possible natural thrombolytic agent against myocardial infarction

Villorita cyprinoides (black clam) is a fresh water clam that belongs as a bivalve to the group of mollusc. The saline extracts from the muscle reveal high titers of agglutination potency on trypsin-treated rabbit erythrocytes. With the help of affinity chromatography a hemolytic protein with lectin activity which could all be inhibited by d-galactose were isolated. The lectins were separated on DEAE-cellulose and the main component was purified after an additional step of gel filtration on sephadex G-75. The main component is a non-glycosylated protein with a molecular weight of 96,560 Da determined by MALDI-ToF, consisting of a single protein chain and characterized by the lack of polymers and intermediate disulfide bonds. The pure main lectin with clot lytic feature shows two bands at molecular weights 36,360 and 26, 520 Da. Optimal inhibition of the pure lectin is achieved by d-galactose containing oligo- and polysaccharides. The lectin activity decreased above 40 °C and was lost at 62 °C, the stability over the pH range between 7.0 and 8.0 and requires divalent cations for their activity. The novel C-type hemolytic lectin for clot lysis from the clam Villorita cyprinoides was identified and evaluated, the purified hemolytic lectin (0.35 mg/ml and 0.175 mg/ml) enhanced clot lysis activity when compared to the different concentration (5 mg/ml and 1 mg/ml) of commercial streptokinase. In the present study identified hemolytic lectin was a rapid and effective clot lytic molecule and could be developed as new drug molecule in future.

Membrane cholesterol and sphingomyelin, and ostreolysin A are obligatory for pore-formation by a MACPF/CDC-like pore-forming protein, pleurotolysin B

The mushroom Pleurotus ostreatus has been reported to produce the hemolytic proteins ostreolysin (OlyA), pleurotolysin A (PlyA) and pleurotolysin B (PlyB). The present study of the native and recombinant proteins dissects out their lipid-binding characteristics and their roles in lipid binding and membrane permeabilization. Using lipid-binding studies, permeabilization of erythrocytes, large unilamellar vesicles of various lipid compositions, and electron microscopy, we show that OlyA, a PlyA homolog, preferentially binds to membranes rich in sterol and sphingomyelin, but it does not permeabilize them. The N-terminally truncated Δ48PlyB corresponds to the mature and active form of native PlyB, and it has a membrane attack complex-perforin (MACPF) domain. Δ48PlyB spontaneously oligomerizes in solution, and binds weakly to various lipid membranes but is not able to perforate them. However, binding of Δ48PlyB to the cholesterol and sphingomyelin membranes, and consequently, their permeabilization is dramatically promoted in the presence of OlyA. On these membranes, Δ48PlyB and OlyA form predominantly 13-meric oligomers. These are rosette-like structures with a thickness of ∼9 nm from the membrane surface, with 19.7 nm and 4.9 nm outer and inner diameters, respectively. When present on opposing vesicle membranes, these oligomers can dimerize and thus promote aggregation of vesicles. Based on the structural and functional characteristics of Δ48PlyB, we suggest that it shares some features with MACPF/cholesterol-dependent cytolysin (CDC) proteins. OlyA is obligatory for the Δ48PlyB permeabilization of membranes rich in cholesterol and sphingomyelin.

Isolation and in vitro partial characterization of hemolytic proteins from the nematocyst venom of the jellyfish Stomolophus meleagris

Jellyfish venom contains various toxins and can cause itching, edema, muscle aches, shortness of breath, blood pressure depression, shock or even death after being stung. Hemolytic protein is one of the most hazardous components in the venom. The present study investigated the hemolytic activity of the nematocyst venom from jellyfish Stomolophus meleagris. Anion exchange chromatography, DEAE Sepharose Fast Flow, and gel filtration chromatography, Superdex200 had been employed to isolate hemolytic proteins from the nematocyst venom of jellyfish S. meleagris. Hemolysis of chicken red blood cells was used to quantify hemolytic potency of crude nematocyst venom and chromatography fractions during the purification process. Native-PAGE profile displayed one protein band in the purified hemolytic protein (SmTX); however, two protein bands with apparent molecular weights of ∼45kDa and 52kDa were observed in the reducing SDS–PAGE analysis. Approximately 70μg/mL of SmTX caused 50% hemolysis (HU50) of the erythrocyte suspension. The hemolytic activity of SmTX was shown to be temperature and pH dependent, with the optimum temperature and pH being 37°C and pH 5.0. The present study is the first report of isolation and partial characterization of hemolytic proteins from the nematocyst venom of the jellyfish S. meleagris. The mechanism of the hemolytic activity of SmTX is not clear and deserves further investigation.

Nano–Bio Interaction between Graphite Oxide Nanoparticles and Human Blood Components

AbstractWe investigated the effect of graphite oxide (GO) nanoparticles, which are an emerging nanomaterial with potential applications as drug‐delivery nanocarriers, on human blood cells and plasma proteins. Graphite oxides were successfully prepared by oxidizing graphite with potassium permanganate and sulfuric acid. Powder X‐ray diffraction patterns, FTIR, and Raman spectra show that the oxidation of graphite worked well and yielded GO nanolayers. To evaluate the interaction of GO with human blood components, we studied its hemolytic effect and protein binding kinetics. The nanoparticles did not show any significant hemolytic effect during 30 min at a very high concentration of 10 mg/mL, showing high compatibility with human blood. The interaction between GO nanoparticles and human blood cells was visualized with optical microscopy. Some nanoparticles were found at the periphery of blood cells, however, significant damages or morphological changes of blood cells upon exposure to nanoparticles were not detected. When we treated GO nanoparticles with plasma proteins, such as human serum albumin, γ‐immunoglobulin, and fibrinogen, they showed concentration‐dependent binding behavior, and the binding constant is comparable with other biocompatible nanoparticles.

Trade-offs shape the evolution of the vector-borne insect pathogen Xenorhabdus nematophila

Our current understanding on how pathogens evolve relies on the hypothesis that pathogens' transmission is traded off against host exploitation. In this study, we surveyed the possibility that trade-offs determine the evolution of the bacterial insect pathogen, Xenorhabdus nematophila. This bacterium rapidly kills the hosts it infects and is transmitted from host cadavers to new insects by a nematode vector, Steinernema carpocapsae. In order to detect trade-offs in this biological system, we produced 20 bacterial lineages using an experimental evolution protocol. These lineages differ, among other things, in their virulence towards the insect host. We found that nematode parasitic success increases with bacteria virulence, but their survival during dispersal decreases with the number of bacteria they carry. Other bacterial traits, such as production of the haemolytic protein XaxAB, have a strong impact on nematode reproduction. We then combined the result of our measurements with an estimate of bacteria fitness, which was divided into a parasitic component and a dispersal component. Contrary to what was expected in the trade-off hypothesis, we found no significant negative correlation between the two components of bacteria fitness. Still, we found that bacteria fitness is maximized when nematodes carry an intermediate number of cells. Our results therefore demonstrate the existence of a trade-off in X. nematophila, which is caused, in part, by the reduction in survival this bacterium causes to its nematode vectors.

Topical application of complement C3 in collagen formulation increases early wound healing

Background: The complement system is composed of bactericidal and hemolytic proteins that increase capillary leakage and inflammatory cell migration. The role of complement C3 to augment wound healing has not yet been studied. Methods: We examined the effects of topical complement C3 formulation at two concentrations (10 and 100 nM) on the rat surgical skin incision model. Skin was examined for maximal breaking strength and sectioned for histological examination. Fibronectin and collagen I content were measured using western blot analysis. Results: There was a statistically significant 74% increase in maximum wound strength with the topical application of 100 nM of C3 at day 3 (850 ± 138 g) when compared to the control rats (490 ± 57 g). Histological correlation was seen with an increased inflammatory cell and fibroblast infiltration in treated wounds as compared to control rats as early as 3 days post-wounding. Western blots revealed increased fibronectin and collagen I levels in C3 treated wounds. Conclusions: Topical application of complement C3 in collagen formulation to skin wounds significantly increases wound healing as early as 3 days after wounding. This is correlated with increased inflammatory cell recruitment and the subsequent early fibroblast migration and increased collagen deposition and organization in wounds.

Effects of quaternization and PEGylation on the biocompatibility, enzymatic degradability and antioxidant activity of chitosan derivatives

Abstract Chitosan-N-trimethylaminoethylmethacrylate chloride (CS-TM) copolymers with different quaternization degrees (DQ, 30 and 50%) were synthesized and further modified with methoxypoly(ethylene glycol) (mPEG) of different molecular weights (MW, 2 and 5 kDa). The hydrophilicity of the resulting copolymers was significantly increased as evidenced by decreased contact angles. PEGylation with higher mPEG MW could significantly reduce the hemolytic potential, protein adsorption, cytotoxicity and intestinal mucosal damage of CS-TM (DQ of 50%, CS-TM50). PEGylation resulted in a considerable increase in the release of reducing sugars following 84-day lysozyme-catalyzed degradation, and an increase in mPEG MW led to a faster degradation of CS-TM50. The antioxidant activity of CS-TM50 was superior to that of PEGylated CS-TM50, exhibiting dose-dependent reducing power and lipid peroxidation inhibition effect. In conclusion, quaternization and subsequent PEGylation of CS with rational modification degree of its free amino group will be a potential strategy for the development of biocompatible and biodegradable CS derivatives.

The effect of hemolytic activity and protein adsorption of coronary stent with different hydrophobic surface

ObjectiveTo investigate the effect of hemolytic activity and protein adsorption of coronary stent with different hydrophobic surface.MethodsThe propyl triethoxysilane, octyltriethoxysilane and 3-(2, 3-epoxypropoxy) propyltrimethoxysila- -ne were modified to the surface...

High-resolution structural insights on the sugar-recognition and fusion tag properties of a versatile β-trefoil lectin domain from the mushroom Laetiporus sulphureus

In this work, we analyzed at high resolution the sugar-binding mode of the recombinant N-terminal ricin-B domain of the hemolytic protein LSLa (LSL(150)) from the mushroom Laetiporus sulphureus and also provide functional in vitro evidence suggesting that, together with its putative receptor-binding role, this module may also increase the solubility of its membrane pore-forming partner. We first demonstrate that recombinant LSL(150) behaves as an autonomous folding unit and an active lectin. We have determined its crystal structure at 1.47Å resolution and also that of the [LSL(150):(lactose)β, γ)] binary complex at 1.67Å resolution. This complex reveals two lactose molecules bound to the β and γ sites of LSL(150), respectively. Isothermal titration calorimetry indicates that LSL(150) binds two lactoses in solution with highly different affinities. Also, we test the working hypothesis that LSL(150) exhibits in vivo properties typical of solubility tags. With this aim, we have fused an engineered version of LSL(150) (LSL(t)) to the N-terminal end of various recombinant proteins. All the designed LSL(150)-tagged fusion proteins were successfully produced at high yield, and furthermore, the target proteins were purified by a straightforward affinity procedure on agarose-based matrices due to the excellent properties of LSL(150) as an affinity tag. An optimized protocol for target protein purification was devised, which involved removal of the LSL(150) tag through in-column cleavage of the fusion proteins with His(6)-tagged TEV endoprotease. These results permitted to set up a novel, lectin-based system for production and purification of recombinant proteins in E. coli cells with attractive biotechnological applications.