An Alternative Nucleobase Code: Characterization of Purine-Purine DNA Double Helices Bearing Guanine-Isoguanine and Diaminopurine 7-Deaza-Xanthine Base Pairs

ChemBioChem ◽  
2008 ◽  
Vol 9 (17) ◽  
pp. 2779-2783 ◽  
Author(s):  
Benjamin D. Heuberger ◽  
Christopher Switzer
Keyword(s):  
Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1042
Author(s):  
Cheepudom ◽  
Lin ◽  
Lee ◽  
Meng

Thermobifida fusca is of biotechnological interest due to its ability to produce an array of plant cell wall hydrolytic enzymes. Nonetheless, only one T. fusca bacteriophage with genome information has been reported to date. This study was aimed at discovering more relevant bacteriophages to expand the existing knowledge of phage diversity for this host species. With this end in view, a thermostable T. fusca bacteriophage P318, which belongs to the Siphoviridae family, was isolated and characterized. P318 has a double-stranded DNA genome of 48,045 base pairs with 3′-extended COS ends, on which 52 putative ORFs are organized into clusters responsible for the order of genome replication, virion morphogenesis, and the regulation of the lytic/lysogenic cycle. In comparison with T. fusca and the previously discovered bacteriophage P1312, P318 has a much lower G+C content in its genome except at the region encompassing ORF42, which produced a protein with unknown function. P1312 and P318 share very few similarities in their genomes except for the regions encompassing ORF42 of P318 and ORF51 of P1312 that are homologous. Thus, acquisition of ORF42 by lateral gene transfer might be an important step in the evolution of P318.


Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 636-641 ◽  
Author(s):  
R Anand ◽  
CD Boehm ◽  
HH Jr Kazazian ◽  
EF Vanin

Abstract We report the characterization of a beta zero-thalassemia in an American Black with unusually high HbA2 and HbF levels. Genomic southern analysis indicated that the individual was heterozygous for a deletion that began within the second intervening sequence of the beta- globin gene and extended approximately 1.4 kb in the 5′ direction. A clone spanning the breakpoint on the abnormal chromosome was isolated and further mapped, and the deletion joint was sequenced. Comparison of the normal beta-globin gene and its 5′ flanking region with the deletion joint sequence indicated that the 5′ breakpoint for this deletion was 484 base pairs (bp) 5′ to the transcriptional start site for the beta-globin gene and the 3′ breakpoint was 908 bp into the beta- globin gene; the deletion removed a total of 1,393 bp. Comparison of the normal 5′ and 3′ breakpoint sequences indicated that this deletion was the result of a “clean” nonhomologous breakage and reunion event; ie, no spurious bases were added during the recombinational event. Analysis of the breakpoints of this deletion together with the breakpoints of two other small deletions involving the beta-globin gene suggests that the breakpoints may occur at DNA polymerase alpha pause sites.


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

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.


2017 ◽  
Vol 13 ◽  
pp. 2671-2681 ◽  
Author(s):  
Jens Müller

In nucleic acid chemistry, metal-mediated base pairs represent a versatile method for the site-specific introduction of metal-based functionality. In metal-mediated base pairs, the hydrogen bonds between complementary nucleobases are replaced by coordinate bonds to one or two transition metal ions located in the helical core. In recent years, the concept of metal-mediated base pairing has found a significant extension by applying it to parallel-stranded DNA duplexes. The antiparallel-stranded orientation of the complementary strands as found in natural B-DNA double helices enforces a cisoid orientation of the glycosidic bonds. To enable the formation of metal-mediated base pairs preferring a transoid orientation of the glycosidic bonds, parallel-stranded duplexes have been investigated. In many cases, such as the well-established cytosine–Ag(I)–cytosine base pair, metal complex formation is more stabilizing in parallel-stranded DNA than in antiparallel-stranded DNA. This review presents an overview of all metal-mediated base pairs reported as yet in parallel-stranded DNA, compares them with their counterparts in regular DNA (where available), and explains the experimental conditions used to stabilize the respective parallel-stranded duplexes.


ChemBioChem ◽  
2006 ◽  
Vol 7 (12) ◽  
pp. 1970-1975 ◽  
Author(s):  
Sadao Hikishima ◽  
Noriaki Minakawa ◽  
Kazuyuki Kuramoto ◽  
Shintaro Ogata ◽  
Akira Matsuda

1988 ◽  
Vol 8 (9) ◽  
pp. 3703-3709
Author(s):  
T Tsukuda ◽  
S Carleton ◽  
S Fotheringham ◽  
W K Holloman

DNA fragments that function as autonomously replicating sequences (ARSs) have been isolated from Ustilago maydis. When inserted into an integrative transforming vector, the fragments increased the frequency of U. maydis transformation several-thousandfold. ARS-containing plasmids were transmitted in U. maydis as extrachromosomal elements through replication. They were maintained at a level of about 25 copies per cell but were mitotically unstable. One ARS characterized in detail, which we called UARS1, was localized to a 1.7-kilobase fragment. UARS1 contained a cluster of active sequences. This element could be reduced further into three separate subfragments, each of which retained ARS activity. The smallest one was 383 base pairs (bp) long. Although not active itself in yeast, this small fragment contained seven 8-bp direct repeats, two contiguous 30-bp direct repeats, and five 11-bp units in both orientations with sequences similar but not identical to the consensus sequence found to be crucial for ARS activity in Saccharomyces cerevisiae.


Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 34
Author(s):  
Vivek Bhakta Mathema ◽  
Supatchara Nakeesathit ◽  
Nicholas J. White ◽  
Arjen M. Dondorp ◽  
Mallika Imwong

Microsatellites can be utilized to explore genotypes, population structure, and other genomic features of eukaryotes. Systematic characterization of microsatellites has not been a focus for several species of Plasmodium, including P. malariae and P. ovale, as the majority of malaria elimination programs are focused on P. falciparum and to a lesser extent P. vivax. Here, five human malaria species (P. falciparum, P. vivax, P. malariae, P. ovale curtisi, and P. knowlesi) were investigated with the aim of conducting in-depth categorization of microsatellites for P. malariae and P. ovale curtisi. Investigation of reference genomes for microsatellites with unit motifs of 1–10 base pairs indicates high diversity among the five Plasmodium species. Plasmodium malariae, with the largest genome size, displays the second highest microsatellite density (1421 No./Mbp; 5% coverage) next to P. falciparum (3634 No./Mbp; 12% coverage). The lowest microsatellite density was observed in P. vivax (773 No./Mbp; 2% coverage). A, AT, and AAT are the most commonly repeated motifs in the Plasmodium species. For P. malariae and P. ovale curtisi, microsatellite-related sequences are observed in approximately 18–29% of coding sequences (CDS). Lysine, asparagine, and glutamic acids are most frequently coded by microsatellite-related CDS. The majority of these CDS could be related to the gene ontology terms “cell parts,” “binding,” “developmental processes,” and “metabolic processes.” The present study provides a comprehensive overview of microsatellite distribution and can assist in the planning and development of potentially useful genetic tools for further investigation of P. malariae and P. ovale curtisi epidemiology.


2010 ◽  
Vol 20 (1) ◽  
pp. 91-99
Author(s):  
R. C. Jena ◽  
K. C. Samal ◽  
P. K. Chand ◽  
B. K. Das

Randomly amplified polymorphic DNA (RAPD) markers were used for the genetic variation and relationship analysis among 12 Mango (Mangifera indica L.) germplasm. Five oligonucleotide primers were employed to amplify DNA from 12 cultivars. PCR amplification with five primers generated 45 reproducible, clear and distinct bands, out of which 41 bands are considered polymorphic and the remaining four fragments (8.88%)  monomorphic. The size of amplified product ranged from 200 (RPI-5) to 3000 base pairs (RPI-1) with an average of nine bands per primer. The average polymorphism in all the 12 cultivars using the five primers was found to be 91.91%. Among all the primers RPI-2 and RPI-4 have shown 100% polymorphism while RPI-5 was found to be least polymorphism (81.81%). One specific band, namely was found with RPI-5, in a particular variety, Chiratpuri. The UPGMA (Unweighted Pair Group Method of Arithmetic Mean) dendrogram based on Jaccard’s similarity coefficient segregated the 12 mango germplasm into two clusters. Langra, Chiratpuri, Pravasankar, Alphanso, Sindhu and Kesar formed one cluster and rest six mango germplasm grouped together into another cluster. Sindhu and Alphanso cultivar pair was very close to each other with highest similarity coefficient (0.78), which was comparatively higher than all other cultivar pairs. On the other hand, Pravasankar and Neelam cultivar pair was more distinct to each other with the lowest intervarietal similarity coefficient 0.38. This study showed clearly that cultivars from Orissa unveiled maximum diversity and indicated the potential of RAPD markers for the identification of management of mango germplasm for breeding purposes.  Key words: Molecular characterization, Mango germplasm, Dversity  D.O.I. 10.3329/ptcb.v20i1.5972 Plant Tissue Cult. & Biotech. 20(1): 91-99, 2010 (June)


2004 ◽  
Vol 31 (2) ◽  
pp. 149 ◽  
Author(s):  
Claudia Stange ◽  
José Tomás Matus ◽  
Alvaro Elorza ◽  
Patricio Arce-Johnson

Nicotiana tabacum cv. Xanthi nn plants are susceptible to infection by most tobamoviruses (TMV). However, such plants display a partial hypersensitive resistance response (HR-like response) to TMV-Cg. The genetic mechanism of the HR-like response has yet not been determined, but it may involve a gene with a function similar to that of a resistance gene, responsible for HR in resistant plants. We have cloned a gene homologous to the resistance N gene, named NH, from Nicotiana Xanthi nn plants. The coding region of NH is 5.028 base pairs (bp) long and has 82.6% nucleotide identity with the N gene. In contrast to the N gene, the NH gene lacks intron 4 and does not have sites for alternative splicing of intron 3. Analysis of its sequence revealed that NH belongs to the TIR / NSB / LRR gene class. We were able to detect stable levels of NH-transcript in Nicotiana Xanthi nn plants from 0 to 18 h post-inoculation (hpi) with TMV-Cg. Transcript levels increased slightly at 24 hpi and dropped below basal values at 48 hpi. The NH transcript was also detected in a range of resistant Nicotiana plants (N. tabacum Xanthi NN, N. glutinosa, N. glauca and N. rustica) suggesting that NH is a homologue of the N gene, rather than an allele. We have cloned and characterised the NH gene (GenBank acc. no. bankit598573 AY535010) from nn susceptible plants and postulate that this gene might be involved in the HR-like response seen in these plants.


Sign in / Sign up

Export Citation Format

Share Document