Dataset Information

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate.

ABSTRACT: Chemically synthesized RNAs with the unnatural L-configuration possess enhanced in vivo stability and nuclease resistance, which is a highly desirable property for pharmacological applications. For a structural comparison, both L- and D-RNA oligonucleotides of a shortened Thermus flavus 5S rRNA A-helix were chemically synthesized. The enantiomeric RNA duplexes were stochiometrically cocrystallized as a racemate, which enabled analysis of the D- and L-RNA enantiomers in the same crystals. In addition to a biochemical investigation, diffraction data were collected to 3.0 A resolution using synchrotron radiation. The crystals belonged to space group P3(1)21, with unit-cell parameters a = b = 35.59, c = 135.30 A, gamma = 120 degrees and two molecules per asymmetric unit.

SUBMITTER: Forster C

PROVIDER: S-EPMC2339724 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate.

Förster Charlotte C Brauer Arnd B E AB Lehmann Daniel D Borowski Tordis T Brode Svenja S Fürste Jens P JP Perbandt Markus M Betzel Christian C Erdmann Volker A VA

Acta crystallographica. Section F, Structural biology and crystallization communications 20070919 Pt 10

Chemically synthesized RNAs with the unnatural L-configuration possess enhanced in vivo stability and nuclease resistance, which is a highly desirable property for pharmacological applications. For a structural comparison, both L- and D-RNA oligonucleotides of a shortened Thermus flavus 5S rRNA A-helix were chemically synthesized. The enantiomeric RNA duplexes were stochiometrically cocrystallized as a racemate, which enabled analysis of the D- and L-RNA enantiomers in the same crystals. In addi ...[more]

PMID: 17909284

Similar Datasets

Project description:BackgroundIn addition to providing phylogenetic relationships, tree making procedures such as parsimony and maximum likelihood can make specific predictions of actual historical sequences. Resurrection of such sequences can be used to understand early events in evolution. In the case of RNA, the nature of parsimony is such that when applied to multiple RNA sequences it typically predicts ancestral sequences that satisfy the base pairing constraints associated with secondary structure. The case for such sequences being actual ancestors is greatly improved, if they can be shown to be biologically functional.ResultsA unique common ancestral sequence of 28 Vibrio 5S ribosomal RNA sequences predicted by parsimony was resurrected and found to be functional in the context of the E. coli cellular environment. The functionality of various point variants and intermediates that were constructed as part of the resurrection were examined in detail. When separately introduced the changes at single stranded positions and individual double variants at base-paired positions were also viable. An additional double variant was examined at a different base-paired position and it was also valid.ConclusionsThe results show that at least in the case of the 5S rRNAs considered here, ancestors predicted by parsimony are likely to be realistic when the prediction is not overly influenced by single outliers. It is especially noteworthy that the phenotype of the predicted ancestors could be anticipated as a cumulative consequence of the phenotypes of the individual variants that comprised them. Thus, point mutation data is potentially useful in evaluating the reasonableness of ancestral sequences predicted by parsimony or other methods. The results also suggest that in the absence of significant tertiary structure constraints double variants that preserve pairing in stem regions will typically be accepted. Overall, the results suggest that it will be feasible to resurrect additional meaningful 5S rRNA ancestors as well as ancestral sequences of many different types of RNA.

Project description:BACKGROUND: Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. MATERIAL AND METHODS: Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. RESULTS: Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. DISCUSSION: Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. CONCLUSION: A new observation involving failure to recognize reflected self-images is reported.

Dataset Information

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate.

Publications

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets