scholarly journals Manual Annotation, Transcriptional Analysis, and Protein Expression Studies Reveal Novel Genes in the agl Cluster Responsible for N Glycosylation in the Halophilic Archaeon Haloferax volcanii

2009 ◽  
Vol 191 (9) ◽  
pp. 3068-3075 ◽  
Author(s):  
Sophie Yurist-Doutsch ◽  
Jerry Eichler

ABSTRACT While Eukarya, Bacteria, and Archaea are all capable of protein N glycosylation, the archaeal version of this posttranslational modification is the least understood. To redress this imbalance, recent studies of the halophilic archaeon Haloferax volcanii have identified a gene cluster encoding the Agl proteins involved in the assembly and attachment of a pentasaccharide to select Asn residues of the surface layer glycoprotein in this species. However, because the automated tools used for rapid annotation of genome sequences, including that of H. volcanii, are not always accurate, a reannotation of the agl cluster was undertaken in order to discover genes not previously recognized. In the present report, reanalysis of the gene cluster that includes aglB, aglE, aglF, aglG, aglI, and aglJ, which are known components of the H. volcanii protein N-glycosylation machinery, was undertaken. Using computer-based tools or visual inspection, together with transcriptional analysis and protein expression approaches, genes encoding AglP, AglQ, and AglR are now described.

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2002
Author(s):  
Maria Pilar Solis-Hernandez ◽  
Carla Martín ◽  
Beatriz García ◽  
Natalia Pérez-López ◽  
Yolanda García-Mesa ◽  
...  

Small leucine-rich proteoglycans (SLRPs) regulate different processes and undergo significant alterations in various diseases. Colon carcinomas (CCs) are heterogeneous pathologies with important clinical and molecular differences depending on their location, which makes it interesting to analyze the alterations in SLRPs in right- and left-sided tumors (RS- and LSCCs). SLRP transcription levels were studied in 32 CCs using qPCR compared to healthy colon mucosae samples from the same patients, 20 of them from LSCCs and the remaining 12 from RSCCs. Protein expression of genes with significant differences in their transcriptions was analyzed by immunohistochemistry. The alterations observed were related to survival data. The arrangement of transcription of SLRPs was quite similar in ascending and descending colon, but RS- and LSCCs displayed different patterns of alteration, with a greater number of deregulations occurring in the latter. The analysis of protein expression also indicated changes in the location of these molecules, largely moving to the cell interior. While podocan underexpression showed a trend toward better outcomes, no differences were observed in terms of overall survival. In vitro studies using the HT29 tumor cell line suggest that deregulation of SLRPs could affect cell proliferation. SLRPs constitute new differential markers of RS- and LSCCs, showing differences dependent on the anatomical location of the tumor.


2020 ◽  
Vol 367 (1) ◽  
Author(s):  
Julia-Beate Tästensen ◽  
Ulrike Johnsen ◽  
Andreas Reinhardt ◽  
Marius Ortjohann ◽  
Peter Schönheit

ABSTRACT The haloarchaeon Haloferax volcanii was found to grow on D-galactose as carbon and energy source. Here we report a comprehensive analysis of D-galactose catabolism in H. volcanii. Genome analyses indicated a cluster of genes encoding putative enzymes of the DeLey–Doudoroff pathway for D-galactose degradation including galactose dehydrogenase, galactonate dehydratase, 2-keto-3-deoxygalactonate kinase and 2-keto-3-deoxy-6-phosphogalactonate (KDPGal) aldolase. The recombinant galactose dehydrogenase and galactonate dehydratase showed high specificity for D-galactose and galactonate, respectively, whereas KDPGal aldolase was promiscuous in utilizing KDPGal and also the C4 epimer 2-keto-3-deoxy-6-phosphogluconate as substrates. Growth studies with knock-out mutants indicated the functional involvement of galactose dehydrogenase, galactonate dehydratase and KDPGal aldolase in D-galactose degradation. Further, the transcriptional regulator GacR was identified, which was characterized as an activator of genes of the DeLey–Doudoroff pathway. Finally, genes were identified encoding components of an ABC transporter and a knock-out mutant of the substrate binding protein indicated the functional involvement of this transporter in D-galactose uptake. This is the first report of D-galactose degradation via the DeLey–Doudoroff pathway in the domain of archaea.


2000 ◽  
Vol 182 (13) ◽  
pp. 3784-3793 ◽  
Author(s):  
Vincent J. J. Martin ◽  
William W. Mohn

ABSTRACT We have cloned and sequenced the dit gene cluster encoding enzymes of the catabolic pathway for abietane diterpenoid degradation by Pseudomonas abietaniphila BKME-9. Thedit gene cluster is located on a 16.7-kb DNA fragment containing 13 complete open reading frames (ORFs) and 1 partial ORF. The genes ditA1A2A3 encode the α and β subunits and the ferredoxin of the dioxygenase which hydroxylates 7-oxodehydroabietic acid to 7-oxo-11,12-dihydroxy-8,13-abietadien acid. The dioxygenase mutant strain BKME-941 (ditA1::Tn5) did not grow on nonaromatic abietanes, and transformed palustric and abietic acids to 7-oxodehydroabietic acid in cell suspension assays. Thus, nonaromatic abietanes are aromatized prior to further degradation. Catechol 2,3-dioxygenase activity of xylEtranscriptional fusion strains showed induction of ditA1and ditA3 by abietic, dehydroabietic, and 7-oxodehydroabietic acids, which support the growth of strain BKME-9, as well as by isopimaric and 12,14-dichlorodehydroabietic acids, which are diterpenoids that do not support the growth of strain BKME-9. In addition to the aromatic-ring-hydroxylating dioxygenase genes, thedit cluster includes ditC, encoding an extradiol ring cleavage dioxygenase, and ditR, encoding an IclR-type transcriptional regulator. Although ditR is not strictly required for the growth of strain BKME-9 on abietanes, aditR::Kmr mutation in aditA3::xylE reporter strain demonstrated that it encodes an inducer-dependent transcriptional activator of ditA3. An ORF with sequence similarity to genes encoding permeases (ditE) is linked with genes involved in abietane degradation.


2002 ◽  
Vol 46 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jean-Denis Docquier ◽  
Fabrizio Pantanella ◽  
Francesco Giuliani ◽  
Maria Cristina Thaller ◽  
Gianfranco Amicosante ◽  
...  

ABSTRACT The sequenced chromosome of Caulobacter crescentus CB15 encodes a hypothetical protein that exhibits significant similarity (30 to 35% identical residues) to metallo-β-lactamases of subclass B3. An allelic variant of this gene (divergent by 3% of its nucleotides) was cloned in Escherichia coli from C. crescentus type strain DSM4727. Expression studies confirmed the metallo-β-lactamase activity of its product, CAU-1. The enzyme produced in E. coli was purified by two ion-exchange chromatography steps. CAU-1 contains a 29-kDa polypeptide with an alkaline isoelectric pH (>9), and unlike the L1 enzyme of Stenotrophomonas maltophilia, the native form is monomeric. Kinetic analysis revealed a preferential activity toward penicillins, carbapenems, and narrow-spectrum cephalosporins, while oxyimino cephalosporins were poorly or not hydrolyzed. Affinities for the various β-lactams were poor overall (Km values were always >100 μM and often >400 μM). The interaction with divalent ion chelators appeared to occur by a mechanism similar to that prevailing in other members of subclass B3. In C. crescentus, the CAU-1 enzyme is produced independently of β-lactam exposure and, interestingly, the bla CAU determinant is bracketed by three other genes, including two genes encoding enzymes involved in methionine biosynthesis and a gene encoding a putative transcriptional regulator, in an operon-like structure. The CAU-1 enzyme is the first example of a metallo-β-lactamase in a member of the α subdivision of the class Proteobacteria.


2010 ◽  
Vol 77 (4) ◽  
pp. 1508-1511 ◽  
Author(s):  
Vishwakanth Y. Potharla ◽  
Shane R. Wesener ◽  
Yi-Qiang Cheng

ABSTRACTThe biosynthetic gene cluster of FK228, an FDA-approved anticancer natural product, was identified and sequenced previously. The genetic organization of this gene cluster has now been delineated through systematic gene deletion and transcriptional analysis. As a result, the gene cluster is redefined to contain 12 genes:depAthroughdepJ,depM, and a newly identified pathway regulatory gene,depR.


2008 ◽  
Vol 190 (13) ◽  
pp. 4754-4758 ◽  
Author(s):  
E. M. Widenbrant ◽  
Hsiu-Hui Tsai ◽  
Carton W. Chen ◽  
C. M. Kao

ABSTRACT We observed a spontaneous amplification of the Streptomyces coelicolor chromosome, including genes encoding biosynthetic enzymes of the antibiotic actinorhodin. A new junction of two tandem segments has, inserted within it, a third copy of a transposable element existing in two places elsewhere in the chromosome, suggesting its involvement in the amplification mechanism.


PROTEOMICS ◽  
2005 ◽  
Vol 5 (2) ◽  
pp. 566-571 ◽  
Author(s):  
Roisean E. Ferguson ◽  
Helen P. Carroll ◽  
Adrian Harris ◽  
Eamonn R. Maher ◽  
Peter J. Selby ◽  
...  

2007 ◽  
Vol 66 (5) ◽  
pp. 1092-1106 ◽  
Author(s):  
Andrew Large ◽  
Claudia Stamme ◽  
Christian Lange ◽  
Zhenhong Duan ◽  
Thorsten Allers ◽  
...  

Author(s):  
Yuki Sasaki ◽  
Ayako Horigome ◽  
Toshitaka Odamaki ◽  
Jin-Zhong Xiao ◽  
Akihiro Ishiwata ◽  
...  

Gum arabic arabinogalactan (AG) protein (AGP) is a unique dietary fiber that is degraded and assimilated by only specific strains of Bifidobacterium longum subsp. longum. Here, we identified a novel 3-O-α-d-galactosyl-α-l-arabinofuranosidase (GAfase) from B. longum JCM7052, and classified it into the glycoside hydrolase family 39 (GH39). GAfase released α-d-Galp-(1→3)-l-Ara and β-l-Arap-(1→3)-l-Ara from gum arabic AGP and β-l-Arap-(1→3)-l-Ara from larch AGP, and the α-d-Galp-(1→3)-l-Ara release activity was found to be 594-fold higher than that of β-l-Arap-(1→3)-l-Ara. The GAfase gene was part of a gene cluster that included genes encoding a GH36 α-galactosidase candidate and ABC transporters for the assimilation of the released α-d-Galp-(1→3)-l-Ara in B. longum. Notably, when α-d-Galp-(1→3)-l-Ara was removed from gum arabic AGP, it was assimilated by both B. longum JCM7052 and the non-assimilative B. longum JCM1217, suggesting that the removal of α-d-Galp-(1→3)-l-Ara from gum arabic AGP by GAfase permitted the cooperative action with type-II AG degradative enzymes in B. longum. The present study provides new insight into the mechanism of gum arabic AGP degradation in B. longum. IMPORTANCE Bifidobacteria harbor numerous carbohydrate-active enzymes that degrade several dietary fibers in the gastrointestinal tract. B. longum JCM7052 is known to exhibit the ability to assimilate gum arabic AGP, but the key enzyme involved in the degradation of gum arabic AGP remains unidentified. Here, we cloned and characterized a GH39 3-O-α-d-galactosyl-α-l-arabinofuranosidase (GAfase) from B. longum JCM7052. The enzyme was responsible for the release of α-d-Galp-(1→3)-l-Ara and β-l-Arap-(1→3)-l-Ara from gum arabic AGP. The presence of a gene cluster including the GAfase gene is specifically observed in gum arabic AGP assimilative strains. However, GAfase-carrier strains may affect GAfase-noncarrier strains that express other type-II AG degradative enzymes. These findings provide insights into the bifidogenic effect of gum arabic AGP.


Sign in / Sign up

Export Citation Format

Share Document