scholarly journals Crystal Structure of the Human tRNA Guanine Transglycosylase Catalytic Subunit QTRT1

Biomolecules ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 81 ◽  
Author(s):  
Sven Johannsson ◽  
Piotr Neumann ◽  
Ralf Ficner

RNA modifications have been implicated in diverse and important roles in all kingdoms of life with over 100 of them present on tRNAs. A prominent modification at the wobble base of four tRNAs is the 7-deaza-guanine derivative queuine which substitutes the guanine at position 34. This exchange is catalyzed by members of the enzyme class of tRNA guanine transglycosylases (TGTs). These enzymes incorporate guanine substituents into tRNAAsp, tRNAAsn tRNAHis, and tRNATyr in all kingdoms of life. In contrast to the homodimeric bacterial TGT, the active eukaryotic TGT is a heterodimer in solution, comprised of a catalytic QTRT1 subunit and a noncatalytic QTRT2 subunit. Bacterial TGT enzymes, that incorporate a queuine precursor, have been identified or proposed as virulence factors for infections by pathogens in humans and therefore are valuable targets for drug design. To date no structure of a eukaryotic catalytic subunit is reported, and differences to its bacterial counterpart have to be deducted from sequence analysis and models. Here we report the first crystal structure of a eukaryotic QTRT1 subunit and compare it to known structures of the bacterial TGT and murine QTRT2. Furthermore, we were able to determine the crystal structure of QTRT1 in complex with the queuine substrate.

2008 ◽  
Vol 375 (3) ◽  
pp. 782-792 ◽  
Author(s):  
Lyann Sim ◽  
Roberto Quezada-Calvillo ◽  
Erwin E. Sterchi ◽  
Buford L. Nichols ◽  
David R. Rose

Biochemistry ◽  
1993 ◽  
Vol 32 (9) ◽  
pp. 2154-2161 ◽  
Author(s):  
Jianhua Zheng ◽  
Daniel R. Knighton ◽  
Lynn F. Ten Eyck ◽  
Rolf Karlsson ◽  
N. Xuong ◽  
...  

2018 ◽  
Vol 12 (1) ◽  
pp. 33-39
Author(s):  
Russel S. Abdulhadi ◽  
Nemat J. Abdulbaqi

Gliotoxin is an important virulence factors in Aspergillus fumigatus. The biosynthesis of this mycotoxin is regulated and expressed by the presence of gliP genes. This study aimed to identify Aspergillus fumigatus isolates in clinical and environmental sources with glip genes using conventional PCR and sequence. To achieve this, DNA was isolated from twenty A. fumigatus isolates using commercial kit. The range of the DNA extracted was 65-210 ng/μl with a purity of 1.5-1.9. Species identification of the A. fumigatus isolates was achieved to a high specificity by using tailored primer. The results showed that all isolates had positive results to the primer and all isolates were able to produce gliotoxin. PCR detected the gliotoxin genes, glip in five isolates. The five PCR product samples were sent for sequence analysis and 25 µl (10 pmol) from the forward primer. The results of all the samples  indicated have a  single band of the desired product of gliP gene of A.fumigatus and the samples sent for sequencing related to molecular weight 190 bp.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5470 ◽  
Author(s):  
Elif Bozcal ◽  
Vahap Eldem ◽  
Sohret Aydemir ◽  
Mikael Skurnik

Background Extraintestinal pathogenic Escherichia coli (ExPEC) is an important bacterium and responsible for many bloodstream infections, including urinary tract infections and even fatal bacteremia. The aim of this research was to investigate whether ExPEC strains isolated from Turkish blood cultures have a relationship between 16S rRNA based phylogenetic clusters and antibiotic resistance profiles, virulence factors or clonal lineages. Methods Phenotypically identified ExPEC blood culture isolates (n = 104) were included in this study. The 16S rRNA partial sequence analysis was performed for genotypic identification of ExPEC isolates. Antibiotic susceptibility and Extended-Spectrum β-Lactamase testing of isolates were performed. Phylogenetic classification (A, B1, B2 and D), Multi Locus Sequence Typing analysis and virulence-associated genes were investigated. Results Based on 16S rRNA partial sequence analysis, 97 out of 104 (93.26%) ExPEC isolates were confirmed as E. coli. Ampicillin (74.22%) and cefuroxime axetil (65.97%) resistances had the highest frequencies among the ExPEC isolates. In terms of phylogenetic classification of ExPEC, D (38.14%, 37/97) was the most prevalent group after A (29.89%, 29/97), B2 (20.61%, 20/97), and B1 (11.34%, 11/97). The sequence types of the 20 ExPEC isolates belonging to the B2 phylogenetic group were analyzed by Multi Locus Sequence Typing. Ten isolates out of 20 (50.0%) were identified as ST131. The other STs were ST95 (n = 1), ST14 (n = 1), ST10 (n = 1), ST69 (n = 1), ST1722 (n = 2), ST141 (n = 1), ST88 (n = 1), ST80 (n = 1), and ST998 (n = 1). Of the ST131 strains, six (60%, 6/10) represented serogroup O25. The most common virulence factor genes were serum resistance factor gene, traT (55.7%) aerobactin siderophore receptor and yersiniabactin encoding genes iutA (45.3%) and fyuA (50.5%), respectively. In addition, PAI (41.2%), iroN (23.7%), hlyA (15.4%), kpsII (13.4%), ompT (13.4%), papG (12.4%), iss (9.3%), cnf1 (7.2%), ibeA (2.06%), and sfaS (2.06%) genes were present in the ExPEC isolates. Conclusion The 16S rRNA-based phylogenetic relationship tree analysis showed that a large cluster was present among 97 ExPEC isolates along with related reference strains. There were 21 main clusters with 32 closely related subclusters. Based on our findings, different clonal lineages of ExPEC can display different antibiotic susceptibilities and virulence properties. We also concluded that virulence factors were not distributed depending on phylogenetic groups (A, B1, B2, and D). The ExPEC isolates belonging to the same phylogenetic group and sequence type could display different resistance and virulence characteristics.


Author(s):  
Sheng Lin ◽  
Hua Chen ◽  
Fei Ye ◽  
Zimin Chen ◽  
Fanli Yang ◽  
...  

2000 ◽  
Vol 297 (3) ◽  
pp. 645-657 ◽  
Author(s):  
Amy C Anderson ◽  
Kathy M Perry ◽  
Douglas M Freymann ◽  
Robert M Stroud

FEBS Letters ◽  
1987 ◽  
Vol 223 (2) ◽  
pp. 340-346 ◽  
Author(s):  
Norbert Berndt ◽  
David G. Campbell ◽  
F.Barry Caudwell ◽  
Philip Cohen ◽  
Edgar F. da Cruz e Silva ◽  
...  

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