Photochemical crosslinking unmodified acetylvalyl-tRNA to 16S RNA at the ribosomal P site

Biochemistry ◽  
1978 ◽  
Vol 17 (13) ◽  
pp. 2524-2530 ◽  
Author(s):  
Ira Schwartz ◽  
James Ofengand
Keyword(s):  
16S Rna ◽  
Photochemical Crosslinking ◽  
Ribosomal P

scholarly journals Covalent crosslinking of tRNA1Val to 16S RNA at the ribosomal P site: identification of crosslinked residues.

1982 ◽  
Vol 79 (18) ◽  
pp. 5450-5454 ◽  
Author(s):  
J. B. Prince ◽  
B. H. Taylor ◽  
D. L. Thurlow ◽  
J. Ofengand ◽  
R. A. Zimmermann
Keyword(s):  
Covalent Crosslinking ◽  
16S Rna ◽  
Site Identification ◽  
Ribosomal P

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

Protein-induced conformational changes in 16S rRNA during assembly of the Escherichia Coli 30S ribosomal subunit: A STEM study

1987 ◽  
Vol 45 ◽  
pp. 910-911
Author(s):  
M. Boublik ◽  
V. Mandiyan ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
16S Rrna ◽  
Conformational Changes ◽  
Ribosomal Proteins ◽  
Structural Changes ◽  
Ribosomal Subunit ◽  
Compact Structure ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
30S Subunit

The aim of this study is to understand the mechanism of 16S rRNA folding into the compact structure of the small 30S subunit of E. coli ribosome. The assembly of the 30S E. coli ribosomal subunit is a sequence of specific interactions of 16S rRNA with 21 ribosomal proteins (S1-S21). Using dedicated high resolution STEM we have monitored structural changes induced in 16S rRNA by the proteins S4, S8, S15 and S20 which are involved in the initial steps of 30S subunit assembly. S4 is the first protein to bind directly and stoichiometrically to 16S rRNA. Direct binding also occurs individually between 16S RNA and S8 and S15. However, binding of S20 requires the presence of S4 and S8. The RNA-protein complexes are prepared by the standard reconstitution procedure, dialyzed against 60 mM KCl, 2 mM Mg(OAc)2, 10 mM-Hepes-KOH pH 7.5 (Buffer A), freeze-dried and observed unstained in dark field at -160°.

Imaging of ribosomal RNA-protein interactions by dark-field STEM

1989 ◽  
Vol 47 ◽  
pp. 250-251
Author(s):  
M. Boublik ◽  
V. Mandiyan ◽  
S. Tumminia ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Nucleic Acid ◽  
16S Rrna ◽  
Dark Field ◽  
Radius Of Gyration ◽  
Central Domain ◽  
The Core ◽  
16S Rna ◽  
30S Subunit ◽  
Core Particles

Success in protein-free deposition of native nucleic acid molecules from solutions of selected ionic conditions prompted attempts for high resolution imaging of nucleic acid interactions with proteins, not attainable by conventional EM. Since the nucleic acid molecules can be visualized in the dark-field STEM mode without contrasting by heavy atoms, the established linearity between scattering cross-section and molecular weight can be applied to the determination of their molecular mass (M) linear density (M/L), mass distribution and radius of gyration (RG). Determination of these parameters promotes electron microscopic imaging of biological macromolecules by STEM to a quantitative analytical level. This technique is applied to study the mechanism of 16S rRNA folding during the assembly process of the 30S ribosomal subunit of E. coli. The sequential addition of protein S4 which binds to the 5'end of the 16S rRNA and S8 and S15 which bind to the central domain of the molecule leads to a corresponding increase of mass and increased coiling of the 16S rRNA in the core particles. This increased compactness is evident from the decrease in RG values from 114Å to 91Å (in “ribosomal” buffer consisting of 10 mM Hepes pH 7.6, 60 mM KCl, 2 m Mg(OAc)2, 1 mM DTT). The binding of S20, S17 and S7 which interact with the 5'domain, the central domain and the 3'domain, respectively, continues the trend of mass increase. However, the RG values of the core particles exhibit a reverse trend, an increase to 108Å. In addition, the binding of S7 leads to the formation of a globular mass cluster with a diameter of about 115Å and a mass of ∽300 kDa. The rest of the mass, about 330 kDa, remains loosely coiled giving the particle a “medusa-like” appearance. These results provide direct evidence that 16S RNA undergoes significant structural reorganization during the 30S subunit assembly and show that its interactions with the six primary binding proteins are not sufficient for 16S rRNA coiling into particles resembling the native 30S subunit, contrary to what has been reported in the literature.

Structural changes in 16S RNA from Escherichia coli upon unfolding by urea

Biopolymers ◽  
1993 ◽  
Vol 33 (11) ◽  
pp. 1747-1755 ◽  
Author(s):  
A. A. Timchenko ◽  
J. Langowski ◽  
I. N. Serdyuk
Keyword(s):  
Escherichia Coli ◽  
Structural Changes ◽  
16S Rna

scholarly journals 716. A Case of Symptomatic Intestinal Spirochetosis

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S409-S409
Author(s):  
Zhi En Chan ◽  
Jasmine Chung Shimin
Keyword(s):  
Venereal Disease ◽  
Lower Abdominal Pain ◽  
Colonic Polyps ◽  
Local Context ◽  
Brachyspira Pilosicoli ◽  
16S Rna ◽  
Intestinal Spirochetosis ◽  
Mucous Discharge ◽  
Treatable Condition ◽  
Brachyspira Aalborgi

Abstract Background Intestinal spirochetosis (IS) is a condition caused by Brachyspira aalborgi and Brachyspira Pilosicoli. Its clinical significance has long been a point of contention with some debating that these spirochetes are simply colonic commensals. It is a condition that is more prevalent in developing nations as well as patients with HIV and the homosexual population. The epidemiology and prevalence of IS has not been studied in the local context. Methods We reviewed a case of a 37-year-old man who presented with a two month history of persistent lower abdominal pain, hematochezia, and increase in mucous discharge per rectum. He is sexually active with multiple male partners, and was previously treated for gonorrhea, chlamydia, and syphilis. His basic laboratory investigations were unremarkable, Venereal Disease Research Laboratory (VDRL) antibody and human immunodeficiency virus (HIV) screen were both non-reactive. Computed tomography of the abdomen was unremarkable. Endoscopic evaluation revealed multiple discrete ulcers measuring 1-2mm seen only in the rectum. Random biopsies of the cecum, ascending colon, transverse colon and descending colon showed mild acute colitis with IS. There was also mild to moderate acute proctitis in the rectum with spirochetes seen. 16s RNA gene sequencing of the biopsy specimen were confirmatory for Brachyspira aalborgi. Investigation findings. A: Discrete Ulcers found in rectum, B: Hemotoxylin and Eosin stained specimen showing proctitis, C: False brush Border appearance D: Spirochetes on Warthin Starry stain Results The patient received a 10 day course of metronidazole with complete resolution of his symptoms. Conclusion This case demonstrates the existence of a treatable condition that can be diagnosed with current available investigations for patients with similar symptoms. Recognising at risk populations can also raise clinical suspicion for this condition. Some studies have found associations between IS with development of colonic polyps and also certain colorectal cancers. Further studies on this treatable condition and its disease burden in the local context should be further explored. Disclosures All Authors: No reported disclosures

Sign in / Sign up

Export Citation Format

Share Document