scholarly journals Characterization of Legumain

2002 ◽  
Vol 383 (11) ◽  
pp. 1813-1816 ◽  
Author(s):  
G. Schwarz ◽  
J. Brandenburg ◽  
M. Reich ◽  
T. Burster ◽  
C. Driessen ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Basic Protein ◽  
Critical Role ◽  
Immunodominant Epitope ◽  
Alternative Substrate ◽  
Asparaginyl Endopeptidase ◽  
Pig Kidney ◽  
Different Types ◽  
Antigen Presenting

Abstract The mammalian legumain, also called asparaginyl endopeptidase (AEP), is critically involved in the processing of bacterial antigens for MHC class II presentation. In order to investigate the substrate specificity of AEP in the P1 position, we created a peptide library and digested it with purified pig kidney AEP. Digestion was less efficient only when proline was in the P1 position. Maximum AEP activity was found in lysosomal fractions of different types of antigen presenting cells (APC). When the multiple sclerosisassociated autoantigen myelin basic protein (MBP) was digested with AEP, the immunodominant epitope 8399 was destroyed. Myoglobin as an alternative substrate was AEP resistant. These results suggest an important, but not necessarily critical role for AEP in lysosomal antigen degradation.

scholarly journals Pig kidney legumain: an asparaginyl endopeptidase with restricted specificity

1999 ◽  
Vol 339 (3) ◽  
pp. 743-749 ◽  
Author(s):  
Pam M. DANDO ◽  
Mara FORTUNATO ◽  
Lorraine SMITH ◽  
C. Graham KNIGHT ◽  
John E. MCKENDRICK ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Tetanus Toxin ◽  
Tertiary Butyl ◽  
Asparaginyl Endopeptidase ◽  
Pig Kidney ◽  
Bait Region ◽  
Substrate Analogues ◽  
Α2 Macroglobulin ◽  
Hydrolysis Of ◽  
Asparagine Residue

Legumain was recently discovered as a lysosomal endopeptidase in mammals [Chen, Dando, Rawlings, Brown, Young, Stevens, Hewitt, Watts and Barrett (1997) J. Biol. Chem. 272, 8090-8098], having been known previously only from plants and invertebrates. It has been shown to play a key role in processing of the C fragment of tetanus toxin for presentation by the MHC class-II system [Manoury, Hewitt, Morrice, Dando, Barrett and Watts (1998) Nature (London) 396, 695-699]. We examine here the specificity of the enzyme from pig kidney by use of protein, oligopeptide and synthetic arylamide substrates, all determinations being made at pH 5.8. In proteins, only about one in ten of the asparaginyl bonds were hydrolysed, and these were mostly predicted to be located at turns on the protein surface. Bonds that were not cleaved in tetanus toxin were cleaved when presented in oligopeptides, sometimes faster than an equivalent oligopeptide based on a bond that was cleaved in the protein. Legumain cleaved the bait region of rat α1-macroglobulin and was ‘trapped’ by the macroglobulin, as most other endopeptidases are, but did not interact with human α2-macroglobulin, which contains no asparagine residue in its bait region. Glycosylation of asparagine totally prevented hydrolysis by legumain. Specificity for arylamide substrates was evaluated with reference to benzyloxycarbonyl-Ala-Ala-Asn-aminomethylcoumarin, and the preference for the P3-position amino acid was Ala > Tyr(tertiary butyl) > Val > Pro > Phe = Tyr > Leu = Gly. There was no hydrolysis of substrate analogues containing mono- or di-N-methylasparagines, L-2-amino-3-ureidopropionic acid or citrulline in the P1 position. We conclude that mammalian legumain appears to be totally restricted to the hydrolysis of asparaginyl bonds in substrates of all kinds. There seem to be no strong preferences for particular amino acids in other subsites, and yet there are still unidentified factors that prevent hydrolysis of many asparaginyl bonds in proteins.

Electron microscopic characterization of diamond thin films and substrates for diamond heteroepitaxial growth

1989 ◽  
Vol 47 ◽  
pp. 592-593
Author(s):  
J.B. Posthill ◽  
R.P. Burns ◽  
R.A. Rudder ◽  
Y.H. Lee ◽  
R.J. Markunas ◽  
...  
Keyword(s):  
Thin Films ◽  
Wide Band ◽  
Deposition Process ◽  
Heteroepitaxial Growth ◽  
Electron Microscopic ◽  
Wide Band Gap ◽  
Lattice Matching ◽  
Different Types ◽  
Diamond Thin Films

Because of diamond’s wide band gap, high thermal conductivity, high breakdown voltage and high radiation resistance, there is a growing interest in developing diamond-based devices for several new and demanding electronic applications. In developing this technology, there are several new challenges to be overcome. Much of our effort has been directed at developing a diamond deposition process that will permit controlled, epitaxial growth. Also, because of cost and size considerations, it is mandatory that a non-native substrate be developed for heteroepitaxial nucleation and growth of diamond thin films. To this end, we are currently investigating the use of Ni single crystals on which different types of epitaxial metals are grown by molecular beam epitaxy (MBE) for lattice matching to diamond as well as surface chemistry modification. This contribution reports briefly on our microscopic observations that are integral to these endeavors.

Allotransplantation of culture-isolated neonatal rat islet tissue. Absence of MHC class II positive antigen-presenting cells in nonimmunogenic islets

Diabetes ◽  
1989 ◽  
Vol 38 (2) ◽  
pp. 146-151 ◽  
Author(s):  
O. D. Hegre ◽  
R. J. Ketchum ◽  
H. Popiela ◽  
C. R. Eide ◽  
R. M. Meloche ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Antigen Presenting Cells ◽  
Class Ii ◽  
Neonatal Rat ◽  
Islet Tissue ◽  
Antigen Presenting

Characterization of Different Types of Biomass Wastes Using Thermogravimetric and ICP-MS Analyses

2020 ◽  
Vol 70 (12) ◽  
pp. 4594-4600
Keyword(s):  
Thermogravimetric Analysis ◽  
Food Industry ◽  
Wood Waste ◽  
Biomass Ash ◽  
Minor Elements ◽  
Ms Analysis ◽  
Icp Ms ◽  
Different Types

The purpose of this study was to characterize some types of biomass wastes resulted from different activities such as: agriculture, forestry and food industry using thermogravimetric and ICP-MS analyses. Also, it was optimized an ICP-MS method for the determination of As, Cd and Pb from biomass ash samples. The ICP-MS analysis revealed that the highest concentration of metals (As, Cd, Pb) was recorded in the wood waste ash sample, also the thermogravimetric analysis indicated that the highest amount of ash was obtained for the same sample (26.82%). The biomass wastes mentioned in this study are alternative recyclable materials, reusable as pellets and briquettes. Keywords: ash, biomass, ICP-MS, minor elements, TG

Characterization of different types of broiler bedding including dehydrated grass and their influence on production

2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Bruna B. Przybulinski ◽  
Rodrigo G. Garcia ◽  
Maria Fernanda de C. Burbarelli ◽  
Claudia M. Komiyama ◽  
Deivid Kelly Barbosa ◽  
...  
Keyword(s):  
Different Types

scholarly journals Ultrafiltration Method for Plasma Protein Binding Studies and Its Limitations

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 382
Author(s):  
Camelia-Maria Toma ◽  
Silvia Imre ◽  
Camil-Eugen Vari ◽  
Daniela-Lucia Muntean ◽  
Amelia Tero-Vescan
Keyword(s):  
Protein Binding ◽  
Plasma Protein Binding ◽  
Plasma Protein ◽  
Specific Binding ◽  
Critical Role ◽  
Volume Ratio ◽  
Binding Studies ◽  
Experimental Conditions ◽  
Key Aspects

Plasma protein binding plays a critical role in drug therapy, being a key part in the characterization of any compound. Among other methods, this process is largely studied by ultrafiltration based on its advantages. However, the method also has some limitations that could negatively influence the experimental results. The aim of this study was to underline key aspects regarding the limitations of the ultrafiltration method, and the potential ways to overcome them. The main limitations are given by the non-specific binding of the substances, the effect of the volume ratio obtained, and the need of a rigorous control of the experimental conditions, especially pH and temperature. This review presents a variety of methods that can hypothetically reduce the limitations, and concludes that ultrafiltration remains a reliable method for the study of protein binding. However, the methodology of the study should be carefully chosen.

scholarly journals Mutator-Suppressible Alleles of rough sheath1 and liguleless3 in Maize Reveal Multiple Mechanisms for Suppression

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 437-446 ◽  
Author(s):  
Lisa Girard ◽  
Michael Freeling
Keyword(s):  
Untranslated Region ◽  
Mutant Allele ◽  
Negative Regulation ◽  
Wild Type ◽  
Knox Gene ◽  
Transcript Accumulation ◽  
Mu Suppression ◽  
Different Types ◽  
Rna Blot Analysis

Abstract Insertions of Mutator transposons into maize genes can generate suppressible alleles. Mu suppression is when, in the absence of Mu activity, the phenotype of a mutant allele reverts to that of its progenitor. Here we present the characterization of five dominant Mu-suppressible alleles of the knox (knotted1-like homeobox) genes liguleless3 and rough sheath1, which exhibit neomorphic phenotypes in the leaves. RNA blot analysis suggests that Mu suppression affects only the neomorphic aspect of the allele, not the wild-type aspect. Additionally, Mu suppression appears to be exerting its effects at the level of transcription or transcript accumulation. We show that truncated transcripts are produced by three alleles, implying a mechanism for Mu suppression of 5′ untranslated region insertion alleles distinct from that which has been described previously. Additionally, it is found that Mu suppression can be caused by at least three different types of Mutator elements. Evidence presented here suggests that whether an allele is suppressible or not may depend upon the site of insertion. We cite previous work on the knox gene kn1, and discuss our results in the context of interactions between Mu-encoded products and the inherently negative regulation of neomorphic liguleless3 and rough sheath1 transcription.

scholarly journals Engineering nucleosomes for generating diverse chromatin assemblies

2021 ◽  
Author(s):  
Zenita Adhireksan ◽  
Deepti Sharma ◽  
Phoi Leng Lee ◽  
Qiuye Bao ◽  
Sivaraman Padavattan ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Dna Nanostructures ◽  
Macromolecular Assemblies ◽  
Maximum Resolution ◽  
Different Types ◽  
Chromatin Structural ◽  
Dna Fragment

Abstract Structural characterization of chromatin is challenging due to conformational and compositional heterogeneity in vivo and dynamic properties that limit achievable resolution in vitro. Although the maximum resolution for solving structures of large macromolecular assemblies by electron microscopy has recently undergone profound increases, X-ray crystallographic approaches may still offer advantages for certain systems. One such system is compact chromatin, wherein the crystalline state recapitulates the crowded molecular environment within the nucleus. Here we show that nucleosomal constructs with cohesive-ended DNA can be designed that assemble into different types of circular configurations or continuous fibers extending throughout crystals. We demonstrate the utility of the method for characterizing nucleosome compaction and linker histone binding at near-atomic resolution but also advance its application for tackling further problems in chromatin structural biology and for generating novel types of DNA nanostructures. We provide a library of cohesive-ended DNA fragment expression constructs and a strategy for engineering DNA-based nanomaterials with a seemingly vast potential variety of architectures and histone chemistries.

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