Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bence Jones proteins can be cleaved specifically by several types of endopeptidases into fragments corresponding to the amino-terminal, variant (VL) portion and to the carboxyl-terminal, constant (CL) portion of the light polypeptide chain. Two types of neutral proteases, designated elastase-like (ELP) and chymotrypsin-like (CLP), have been isolated and purified from human polymorphonuclear leukocytes. Because these proteases have defined proteolytic activity under physiologic conditions for several types of human proteins, we investigated their effect on human Bence Jones proteins. Incubation of kappa-type or lambda-type Bence Jones proteins with ELP or CLP under appropriate conditions resulted in cleavage of both types of light chains as evident by immunochemical and electrophoretic analyses. Treatment with ELP or CLP of one kappa Bence Jones protein resulted in the formation of a single component that had antigenic and electrophoretic properties similar to the VL fragment derived from pepsin digestion of the native protein. No component corresponding to the CL could be detected immunochemically or electrophoretically. Studies of isolated pepsin-labile (37 degrees C) and pepsin-stable (55 degrees C) CL fragments demonstrated the marked susceptibility of the carboxyl-terminal half of the light chain to proteolysis by the leukocyte-derived neutral proteases. Incubation with ELP of three other kappa Bence Jones proteins and three reduced-alkylated lambda Bence Jones proteins resulted, in each case, in the formation of a homogeneous component which was electrophoretically and immunochemically distinct from the pepsin-derived VL fragment. An identical component could also be formed by incubating a pepsin-derived VL fragment with ELP. In the ELP-treated samples, no CL-related material was detected electrophoretically or immunochemically with antisera possessing specificity for CL antigenic determinants present on the unfolded light polypeptide chain or on the isolated CL. The component formed by ELP or CLP treatment of certain Bence Jones proteins thus appears to be VL-related, but lacks the idiotypic antigenic determinant present on the native protein. In this respect, these neutral protease-derived light chain components are similar to the amyloid-like VL fragments generated in vitro from certain endopeptidase-treated Bence Jones proteins.
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PMID:Bence Jones proteins and light chains of immunoglobulins. XIII. Effect of elastase-like and chymotrypsin-like neutral proteases derived from human granulocytes on Bence Jones proteins. 6 Apr 45

Two monoclonal antibodies which reacted with the epidermal cell surface (SF-1) and the dermal-epidermal-junction (SF-2), respectively, were obtained by immunizing mice with partially-purified human epibolin. The corresponding antigens were partially purified from fetal bovine serum by affinity chromatography using these antibodies. SDS-polyacrylamide gel electrophoresis showed that these antigens contained polypeptide components with molecular weights different from that of epibolin (mol. wt. 65,000 daltons); SF-1 antigen had a 68,000 dalton main component, and SF-2 antigen a broad 58,000-61,000 dalton main component. Both of these partially-purified antigens promoted the spreading of dissociated pig epidermal cells. SF-2 antigen also promoted the spreading of Pam cells (a murine keratinocyte line). The results suggest that proteins capable of promoting epidermal cell spreading may be present on the epidermal cell surface and at the dermal-epidermal junction. However, their physiological role in keratinization remains to be elucidated.
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PMID:Monoclonal antibodies against epidermal cell surface and dermal-epidermal junction: antigens which may be epidermal cell spreading factors. 242 42

Genetically engineered elastin-like polypeptides consisting of Val-Pro-Gly-X-Gly repeats, where X was chosen to be Lys every 7 or 17 pentapeptides (otherwise X was Val), were synthesized and expressed in E. coli, purified, and chemically cross-linked using tris-succinimidyl aminotriacetate to produce hydrogels. Swelling experiments indicate hydrogel mass decreases by 80-90% gradually over an approximate 50 degrees C temperature range. Gels ranged in stiffness from 0.24 to 3.7 kPa at 7 degrees C and from 1.6 to 15 kPa at 37 degrees C depending on protein concentration, lysine content, and molecular weight. Changes in gel stiffness and loss angle with cross-linking formulation suggest a low-temperature gel structure that is nearly completely elastic, where force is transmitted almost exclusively through fully extended polypeptide chains and chemical cross-links, and a high-temperature gel structure, where ELP chains are contracted and force is transmitted through chemical cross-links as well as frictional contact between polypeptide chains.
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PMID:Swelling and mechanical behaviors of chemically cross-linked hydrogels of elastin-like polypeptides. 1274 72

The FATE gene maps to Xq28 where one case of a translocation breakpoint has been found in an infertile man. Moreover, the FATE promoter contains a putative SF-1-binding site, and FATE has been proposed as representing a target gene of SF-1 in testicular development or germ cell differentiation. This study presents a complete mutational screening of the FATE gene in a random group of 144 infertile males. Four polymorphisms and two mutations were found. Three of the polymorphisms, viz., 741C-->T, 905A-->C, and 3985C-->T, occurred in exon 5 and intron 2 and did not alter the deduced polypeptide. One polymorphism resulted in the conservative amino acid exchange, A10 V, in 16.0% of the patients. This substitution occurred with similar frequencies in the control groups, indicating that the mutation does not affect fertility in men or women. The two mutations caused the non-conservative amino acid substitutions S125R (patient 1) and I34T (patient 2). A family study (patient 1) revealed, however, that S125R was inherited and that a fertile male family member carried the mutation. Patient 2 did not have relevant family members who could be examined. Thus, this study has shown that only 1.4% of infertile men have mutations in the FATE gene, and that some of these mutations do not singly cause infertility. Hence, FATE may not play an important role in the disease-state of infertile men attending fertility clinics. However, FATE mutations cannot be excluded as being a contributing factor in some cases of male infertility.
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PMID:Mutational analysis of the human FATE gene in 144 infertile men. 1281 41

Cells lacking KTI12 or Elongator (ELP) genes are insensitive to the toxin zymocin and also share more general phenotypes. Moreover, data from low stringency immunoprecipitation experiments suggest that Elongator and Kti12 may interact. However, the precise relationship between these factors has not been determined. Here we use a variety of approaches to investigate the possibility that Elongator and Kti12 functionally overlap. Native Kti12 purified to virtual homogeneity under stringent conditions is a single polypeptide, but depletion of Kti12 from a yeast extract results in co-depletion of Elongator, indicating that these factors do interact. Indeed, biochemical evidence suggests that Elongator and Kti12 form a fragile complex under physiological salt conditions. Purified Kti12 does not affect Elongator histone acetyltransferase activity in vitro. However, a variety of genetic experiments comparing the effects of mutation in ELP3 and KTI12 alone and in combination with other transcription factor mutations clearly demonstrate a significant functional overlap between Elongator and Kti12 in vivo. Intriguingly, chromatin immunoprecipitation experiments show that Kti12 is associated with chromatin throughout the genome, even in non-transcribed regions and in the absence of Elongator. Conversely, RNA-immunoprecipitation experiments indicate that Kti12 only plays a minor role for Elongator association with active genes. Together, these experiments indicate a close physical and functional relationship between Elongator and the highly conserved Kti12 protein.
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PMID:Physical and functional interaction between Elongator and the chromatin-associated Kti12 protein. 1577 87

Elastin-like polypeptides are biopolymers composed of the pentapeptide repeat Val-Pro-Gly-Xaa-Gly. Elastin-like polypeptides are soluble in aqueous solution below their transition temperature, but they hydrophobically collapse and aggregate when the temperature is raised above the transition temperature. Previous studies have suggested that the aggregation of these polypeptides in response to externally applied hyperthermia may be exploited in the use of elastin-like polypeptide for thermally targeted drug delivery. This work shows the application of elastin-like polypeptide as a delivery vehicle for a short peptide that can inhibit the transcriptional function of a specific oncogene. The coding sequence for elastin-like polypeptide was modified by the addition of the membrane translocating sequence penetratin and a peptide derived from helix 1 of the helix-loop-helix region of c-Myc (H1-S6A,F8A), known to inhibit c-Myc transcriptional function. The designed polypeptide (Pen-ELP-H1) was then expressed and purified from Escherichia coli. Cellular uptake of Pen-ELP-H1 is enhanced by both the penetratin sequence and by the hyperthermia-induced phase transition as shown by flow cytometry studies. Using immunofluorescence and reverse transcription-PCR, we show that Pen-ELP-H1 is able to disrupt the nuclear localization of c-Myc and inhibit transcriptional activation by c-Myc. Cell proliferation studies showed that Pen-ELP-H1 inhibits growth of MCF-7 cells. Furthermore, the use of hyperthermia increased the antiproliferative effect of a thermally responsive Pen-ELP-H1 approximately 2-fold compared with a nonthermally responsive control polypeptide. These studies show that genetically engineered elastin-like polypeptide carriers may provide a new way to thermally target specific oncogene inhibitors to solid tumors.
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PMID:Application of thermally responsive polypeptides directed against c-Myc transcriptional function for cancer therapy. 1602 Jun 65

Translocation through the plasma membrane is a major limiting step for the cellular delivery of macromolecules. Several cell penetrating peptides (CPP) have been demonstrated to efficiently internalize various molecular cargo to targets inside eukaryotic cells. In this study, the efficiency and mechanism of cellular uptake of the CPPs penetratin, Tat, and MTS fused to elastin-like polypeptides (CPP-ELP) were evaluated. Elastin-like polypeptides are biopolymers with features that make them useful as polymeric carriers for the delivery of therapeutics. Therefore, improving efficiency of cellular uptake by fusing ELPs to CPPs and understanding the mechanism of their cellular internalization could contribute to development of new therapeutic approaches. Flow cytometry and confocal fluorescence microscopy were used to elucidate the mechanism of CPP-ELP uptake. The internalization of all CPP-ELPs was impaired dramatically at 4 degrees C, under ATP depletion conditions, and with hyperosmolar sucrose, implicating involvement of an endocytic pathway for CPP-ELP internalization. Penetratin was identified as the most effective CPP for delivering ELP. Finally, in order to demonstrate the potential of CPP-ELP for drug delivery, a fusion polypeptide was made containing penetratin, ELP, and a peptide derived from the cyclin-dependent kinase inhibitor p21. This polypeptide was shown to inhibit proliferation of SKOV-3 and HeLa cells by slowing their growth rate.
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PMID:Evaluation of cell penetrating peptides fused to elastin-like polypeptide for drug delivery. 1615 13

The production of recombinant proteins in plants is an active area of research and many different high-value proteins have now been produced in plants. Tobacco leaves have many advantages for recombinant protein production particularly since they allow field production without seeds, flowers or pollen and therefore provide for contained production. Despite these biosafety advantages recombinant protein accumulation in leaves still needs to be improved. Elastin-like polypeptides are repeats of the amino acids "VPGXG" that undergo a temperature dependant phase transition and have utility in the purification of recombinant proteins but can also enhance the accumulation of recombinant proteins they are fused to. We have used a 11.3 kDa elastin-like polypeptide as a fusion partner for three different target proteins, human interleukin-10, murine interleukin-4 and the native major ampullate spidroin protein 2 gene from the spider Nephila clavipes. In both transient analyses and stable transformants the concentrations of the fusion proteins were at least an order of magnitude higher for all of the fusion proteins when compared to the target protein alone. Therefore, fusions with a small ELP tag can be used to significantly enhance the accumulation of a range of different recombinant proteins in plant leaves.
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PMID:Elastin-like polypeptide fusions enhance the accumulation of recombinant proteins in tobacco leaves. 1710 68

In this paper we discuss improvements to our previously reported ELP-intein purification system described by Banki et al. [M.R. Banki, L. Feng, D.W. Wood, Simple bioseparations using self-cleaving elastin-like polypeptide tags, Nat. Methods 2 (2005) 659-661; W.Y. Wu, C. Mee, F. Califano, R. Banki, D.W. Wood, Recombinant protein purification by self-cleaving aggregation tag, Nat. Protoc. 1 (2006) 2257-2262]. This method is based on the selective and reversible precipitation of ELP-tagged target proteins by gentle heating in the presence of high concentrations of sodium chloride. A critical aspect of this system is that the ELP tag is induced to self-cleave by a mild pH shift after purification. An examination of the Hofmeister series of ions suggested that salts other than sodium chloride may be more efficient for ELP precipitation. Specifically, by replacing sodium chloride with ammonium sulfate to induce ELP aggregation, we were able to reduce the required salt concentration by almost 4-fold, and the precipitation steps could be conducted at room temperature instead of 37 degrees C. This results in a cheaper, gentler, and more scaleable purification method. To demonstrate these advantages, green fluorescent protein and beta-lactamase were purified using the newly optimized conditions in side-by-side comparisons to the previous method. The results indicate that both specific activity and yield were improved with the new conditions. These improvements thus significantly increase the attractiveness of this highly general and economical method for recombinant protein purification.
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PMID:Optimization of ELP-intein mediated protein purification by salt substitution. 1934 65

The effects of urea, tetramethyl urea (TMU), and trimethylamine N-oxide (TMAO) on the structure and dynamics of aqueous solutions are studied using molecular dynamics simulations. It was found that urea has little effects on the water-water hydrogen-bond length and angle distributions except that it induces a slight collapse of the second shell in the hydrogen-bonding network. TMU and TMAO both strengthen the individual hydrogen bonds and significantly slow the orientational relaxation of water, but have opposite effects on the second shell structure of the hydrogen-bonding network: TMU distorts while TMAO enhances the tetrahedral water structure. Furthermore, TMAO significantly weakens the interactions between the amide carbonyl group and the water molecules, while TMU and urea both strengthen these interactions, with the effect of urea being much less significant than that of TMU. These conclusions are supported by molecular dynamics simulations of three different systems: a model amide compound CH(3)-NH-CO-CH(3) (NMA), and two polypeptides, GB1 and ELP. Consistent with earlier studies, we also found that urea interacts strongly with the carbonyl group through direct hydrogen bonding. The simulations for the denaturation of the polypeptide GB1 in urea solutions showed that the breaking of its native hydrogen bonds follows a step-by-step process and each step is strongly coupled to the formation of water-carbonyl hydrogen bonds, and to a less extent to the urea-carbonyl hydrogen-bond formation. Our simulation results reveal the potential importance of the indirect effects of cosolvents in protein denaturation or structure protection, particularly through modifying of the water-amide interactions.
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PMID:Effects of urea, tetramethyl urea, and trimethylamine N-oxide on aqueous solution structure and solvation of protein backbones: a molecular dynamics simulation study. 1992 71


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