Characterization of Posttranslational Modifications of Human A33 Antigen, a Novel Palmitoylated Surface Glycoprotein of Human Gastrointestinal Epithelium

1997 ◽  
Vol 236 (3) ◽  
pp. 682-686 ◽  
Author(s):  
Gerd Ritter ◽  
Leonard S. Cohen ◽  
Edouard C. Nice ◽  
Bruno Catimel ◽  
Antony W. Burgess ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Surface Glycoprotein ◽  
Gastrointestinal Epithelium ◽  
Antigen A ◽  
Human Gastrointestinal Epithelium

Micro-sequencing strategies for the human A33 antigen, a novel surface glycoprotein of human gastrointestinal epithelium

1998 ◽  
Vol 798 (1-2) ◽  
pp. 91-101 ◽  
Author(s):  
Robert L Moritz ◽  
Gerd Ritter ◽  
Bruno Catimel ◽  
Leonard S Cohen ◽  
Sydney Welt ◽  
...  
Keyword(s):  
Surface Glycoprotein ◽  
Gastrointestinal Epithelium ◽  
Antigen A ◽  
Human Gastrointestinal Epithelium

scholarly journals Insights into the Functionality of the Putative Residues Involved in Enterocin AS-48 Maturation

2010 ◽  
Vol 76 (21) ◽  
pp. 7268-7276 ◽  
Author(s):  
Rubén Cebrián ◽  
Mercedes Maqueda ◽  
José Luis Neira ◽  
Eva Valdivia ◽  
Manuel Martínez-Bueno ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
High Efficiency ◽  
Specific Protein ◽  
Culture Conditions ◽  
Site Directed Mutagenesis ◽  
Circular Structure ◽  
Cleavage Enzyme ◽  
Site Recognition ◽  
Biosynthetic Machinery

ABSTRACT AS-48 is a 70-residue, α-helical, cationic bacteriocin produced by Enterococcus faecalis and is very singular in its circular structure and its broad antibacterial spectrum. The AS-48 preprotein consists of an N-terminal signal peptide (SP) (35 residues) followed by a proprotein moiety that undergoes posttranslational modifications to yield the mature and active circular protein. For the study of the specificity of the region of AS-48 that is responsible for maturation, three single mutants have been generated by site-directed mutagenesis in the as-48A structural gene. The substitutions were made just in the residues that are thought to constitute a recognition site for the SP cleavage enzyme (His-1, Met1) and in those involved in circularization (Met1, Trp70). Each derivative was expressed in the enterococcal JH2-2 strain containing the necessary native biosynthetic machinery for enterocin production. The importance of these derivatives in AS-48 processing has been evaluated on the basis of the production and structural characterization of the corresponding derivatives. Notably, only two of them (Trp70Ala and Met1Ala derivatives) could be purified in different forms and amounts and are characterized for their bactericidal activity and secondary structure. We could not detect any production of AS-48 in JH2-2(pAM401-81 His-1Ile ) by using the conventional chromatographic techniques, despite the high efficiency of the culture conditions applied to produce this enterocin. Our results underline the different important roles of the mutated residues in (i) the elimination of the SP, (ii) the production levels and antibacterial activity of the mature proteins, and (iii) protein circularization. Moreover, our findings suggest that His-1 is critically involved in cleavage site recognition, its substitution being responsible for the blockage of processing, thereby hampering the production of the specific protein in the cellular culture supernatant.

Biotransformations and cytotoxicity of graphene and inorganic two-dimensional nanomaterials using simulated digestions coupled with a triculture in vitro model of the human gastrointestinal epithelium

2021 ◽  
Author(s):  
Lila Bazina ◽  
Dimitrios Bitounis ◽  
Xiaoqiong Cao ◽  
Glen M. DeLoid ◽  
Dorsa Parviz ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Engineered Nanomaterials ◽  
Two Dimensional ◽  
Gastrointestinal Epithelium ◽  
Vitro Model ◽  
Human Gastrointestinal Epithelium

Background: engineered nanomaterials (ENMs) have already made their way into myriad applications and products across multiple industries.

Protein pIShifts due to Posttranslational Modifications in the Separation and Characterization of Proteins

2005 ◽  
Vol 77 (9) ◽  
pp. 2745-2755 ◽  
Author(s):  
Kan Zhu ◽  
Jia Zhao ◽  
David M. Lubman ◽  
Fred R. Miller ◽  
Timothy J. Barder
Keyword(s):  
Posttranslational Modifications

scholarly journals Biochemical and molecular characterization of N66 from the shell ofPinctada mazatlanica

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7212
Author(s):  
Crisalejandra Rivera-Perez ◽  
Catalina Magallanes-Dominguez ◽  
Rosa Virginia Dominguez-Beltran ◽  
Josafat Jehu Ojeda-Ramirez de Areyano ◽  
Norma Y. Hernandez-Saavedra
Keyword(s):  
Posttranslational Modifications ◽  
Protein A ◽  
Pearl Oyster ◽  
Peptide Sequence ◽  
Calcium Carbonate Precipitation ◽  
Base Pairs ◽  
Shell Matrix ◽  
Glycosylation Sites ◽  
Shell Matrix Proteins

Mollusk shell mineralization is a tightly controlled process made by shell matrix proteins (SMPs). However, the study of SMPs has been limited to a few model species. In this study, the N66 mRNA of the pearl oysterPinctada mazatlanicawas cloned and functionally characterized. The full sequence of the N66 mRNA comprises 1,766 base pairs, and encodes one N66 protein. A sequence analysis revealed that N66 contained two carbonic anhydrase (CA) domains, a NG domain and several glycosylation sites. The sequence showed similarity to the CA VII but also with its homolog protein nacrein. The native N66 protein was isolated from the shell and identified by mass spectrometry, the peptide sequence matched to the nucleotide sequence obtained. Native N66 is a glycoprotein with a molecular mass of 60–66 kDa which displays CA activity and calcium carbonate precipitation ability in presence of different salts. Also, a recombinant form of N66 was produced inEscherichia coli, and functionally characterized. The recombinant N66 displayed higher CA activity and crystallization capability than the native N66, suggesting that the lack of posttranslational modifications in the recombinant N66 might modulate its activity.

scholarly journals N-glycan chitobiose core biosynthesis by Agl24 strengthens the hypothesis of an archaeal origin of the eukaryal N-glycosylation

2021 ◽  
Author(s):  
Benjamin H. Meyer ◽  
Ben A. Wagstaff ◽  
Panagiotis S. Adam ◽  
Sonja-Verena Albers ◽  
Helge C. Dorfmueller
Keyword(s):  
Posttranslational Modifications ◽  
Biochemical Characterization ◽  
Similar Process ◽  
List Type ◽  
Histidine Residue ◽  
Functional Importance ◽  
Domains Of Life ◽  
Distant Relation ◽  
Identification And Characterization

AbstractProtein N-glycosylation is the most common posttranslational modifications found in all three domains of life. The crenarchaeal N-glycosylation begins with the synthesis of a lipid-linked chitobiose core structure, identical to that in eukaryotes. Here, we report the identification of a thermostable archaeal beta-1,4-N-acetylglucosaminyltransferase, named archaeal glycosylation enzyme 24 (Agl24), responsible for the synthesis of the N-glycan chitobiose core. Biochemical characterization confirmed the function as an inverting β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase. Substitution of a conserved histidine residue, found also in the eukaryotic and bacterial homologs, demonstrated its functional importance for Agl24. Furthermore, bioinformatics and structural modeling revealed strong similarities between Agl24 and both the eukaryotic Alg14/13 and a distant relation to the bacterial MurG, which catalyze the identical or a similar process, respectively. Our data, complemented by phylogenetic analysis of Alg13 and Alg14, revealed similar sequences in Asgardarchaeota, further supporting the hypothesis that the Alg13/14 homologs in eukaryotes have been acquired during eukaryogenesis.HighlightsFirst identification and characterization of a thermostable β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase (GT family 28) in Archaea.A highly conserved histidine, within a GGH motif in Agl24, Alg14, and MurG, is essential for function of Agl24.Agl24-like homologs are broadly distributed among Archaea.The eukaryotic Alg13 and Alg14 are closely related to the Asgard homologs, suggesting their acquisition during eukaryogenesis.

Characterization of VSG gene expression site promoters and promoter-associated DNA rearrangement events

1991 ◽  
Vol 11 (5) ◽  
pp. 2467-2480 ◽  
Author(s):  
K Gottesdiener ◽  
H M Chung ◽  
S D Brown ◽  
M G Lee ◽  
L H Van der Ploeg
Keyword(s):  
Transcriptional Control ◽  
Transcription Unit ◽  
Surface Glycoprotein ◽  
Dna Rearrangement ◽  
Cell Surface Glycoprotein ◽  
Polycistronic Transcription ◽  
Variant Cell ◽  
Expression Site ◽  
Simple Sequence

The expressed variant cell surface glycoprotein (VSG) gene of Trypanosoma brucei is located at the 3' end of a large, telomeric, polycistronic transcription unit or expression site. We show that the region 45 kb upstream of the VSG gene, in the expression site on a 1.5-Mb chromosome, contains at least two promoters that are arranged in tandem, directing the transcription of the expression site. DNA rearrangement events occur specifically, at inactivation of the expression site, and these events delete the most upstream transcribed region and replace it with a large array of simple-sequence DNA, leaving the downstream promoter intact. Because of the placement of simple-sequence DNA, the remaining downstream promoter now becomes structurally identical to previously described VSG promoters. The downstream promoter is repetitive in the genome, since it is present at several different expression sites. Restriction fragment length polymorphism mapping allows grouping of the expression sites into two families, those with and those without an upstream transcription unit, and the DNA rearrangement events convert the expression sites from one type to the other. Deletion of the upstream transcription unit also leads to the loss of several steady-state RNAs. The findings may indicate a role for promoter-associated DNA rearrangement events, and/or interactions between tandemly arranged promoters, in expression site transcriptional control.

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