scholarly journals The structure of the human mitochondrial ribosome

Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 95-98 ◽  
Author(s):  
Alexey Amunts ◽  
Alan Brown ◽  
Jaan Toots ◽  
Sjors H. W. Scheres ◽  
V. Ramakrishnan

The highly divergent ribosomes of human mitochondria (mitoribosomes) synthesize 13 essential proteins of oxidative phosphorylation complexes. We have determined the structure of the intact mitoribosome to 3.5 angstrom resolution by means of single-particle electron cryogenic microscopy. It reveals 80 extensively interconnected proteins, 36 of which are specific to mitochondria, and three ribosomal RNA molecules. The head domain of the small subunit, particularly the messenger (mRNA) channel, is highly remodeled. Many intersubunit bridges are specific to the mitoribosome, which adopts conformations involving ratcheting or rolling of the small subunit that are distinct from those seen in bacteria or eukaryotes. An intrinsic guanosine triphosphatase mediates a contact between the head and central protuberance. The structure provides a reference for analysis of mutations that cause severe pathologies and for future drug design.

2019 ◽  
Vol 12 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Sivagnanam Rajamanickam Mani Sekhar ◽  
Siddesh Gaddadevara Matt ◽  
Sunilkumar S. Manvi ◽  
Srinivasa Krishnarajanagar Gopalalyengar

Background: Essential proteins are significant for drug design, cell development, and for living organism survival. A different method has been developed to predict essential proteins by using topological feature, and biological features. Objective: Still it is a challenging task to predict essential proteins effectively and timely, as the availability of protein protein interaction data depends on network correctness. Methods: In the proposed solution, two approaches Mean Weighted Average and Recursive Feature Elimination is been used to predict essential proteins and compared to select the best one. In Mean Weighted Average consecutive slot data to be taken into aggregated count, to get the nearest value which considered as prescription for the best proteins for the slot, where as in Recursive Feature Elimination method whole data is spilt into different slots and essential protein for each slot is determined. Results: The result shows that the accuracy using Recursive Feature Elimination is at-least nine percentages superior when compared to Mean Weighted Average and Betweenness centrality. Conclusion: Essential proteins are made of genes which are essential for living being survival and drug design. Different approaches have been proposed to anticipate essential proteins using either experimental or computation methods. The experimental result show that the proposed work performs better than other approaches.


Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 523
Author(s):  
Marianne Lebbad ◽  
Jadwiga Winiecka-Krusnell ◽  
Christen Rune Stensvold ◽  
Jessica Beser

The intestinal protozoan parasite Cryptosporidium is an important cause of diarrheal disease worldwide. The aim of this study was to expand the knowledge on the molecular epidemiology of human cryptosporidiosis in Sweden to better understand transmission patterns and potential zoonotic sources. Cryptosporidium-positive fecal samples were collected between January 2013 and December 2014 from 12 regional clinical microbiology laboratories in Sweden. Species and subtype determination was achieved using small subunit ribosomal RNA and 60 kDa glycoprotein gene analysis. Samples were available for 398 patients, of whom 250 (63%) and 138 (35%) had acquired the infection in Sweden and abroad, respectively. Species identification was successful for 95% (379/398) of the samples, revealing 12 species/genotypes: Cryptosporidium parvum (n = 299), C. hominis (n = 49), C. meleagridis (n = 8), C. cuniculus (n = 5), Cryptosporidium chipmunk genotype I (n = 5), C. felis (n = 4), C. erinacei (n = 2), C. ubiquitum (n = 2), and one each of C. suis, C. viatorum, C. ditrichi, and Cryptosporidium horse genotype. One patient was co-infected with C. parvum and C. hominis. Subtyping was successful for all species/genotypes, except for C. ditrichi, and revealed large diversity, with 29 subtype families (including 4 novel ones: C. parvum IIr, IIs, IIt, and Cryptosporidium horse genotype VIc) and 81 different subtypes. The most common subtype families were IIa (n = 164) and IId (n = 118) for C. parvum and Ib (n = 26) and Ia (n = 12) for C. hominis. Infections caused by the zoonotic C. parvum subtype families IIa and IId dominated both in patients infected in Sweden and abroad, while most C. hominis cases were travel-related. Infections caused by non-hominis and non-parvum species were quite common (8%) and equally represented in cases infected in Sweden and abroad.


1986 ◽  
Vol 261 (11) ◽  
pp. 5187-5193
Author(s):  
M N Schnare ◽  
T Y Heinonen ◽  
P G Young ◽  
M W Gray

1996 ◽  
Vol 31 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Gary W. Saunders ◽  
Isabelle M. Strachan ◽  
John A. West ◽  
Gerald T. Kraft

1996 ◽  
Vol 67 (3) ◽  
pp. 316-317 ◽  
Author(s):  
Norman J. Pieniazek ◽  
Alexandre J. da Silva ◽  
Susan B. Slemenda ◽  
Govinda S. Visvesvara ◽  
Timothy J. Kurtti ◽  
...  

2020 ◽  
Author(s):  
Caillan Crowe-McAuliffe ◽  
Hiraku Takada ◽  
Victoriia Murina ◽  
Christine Polte ◽  
Sergo Kasvandik ◽  
...  

SummaryIn all branches of life, stalled translation intermediates are recognized and processed by ribosome-associated quality-control (RQC) pathways. RQC begins with splitting of stalled ribosomes, leaving an unfinished polypeptide still attached to the large subunit. Ancient and conserved NEMF family RQC proteins target these incomplete proteins for degradation by the addition of C-terminal ‘tails.’ How such tailing can occur without the regular suite of translational components is, however, unclear. Using ex vivo single-particle cryo-EM, we show that C-terminal tailing in Bacillus subtilis is mediated by NEMF protein RqcH in concert with YabO, a protein homologous to, yet distinct from, Hsp15. Our structures reveal how these factors mediate tRNA movement across the ribosomal 50S subunit to synthesize polypeptides in the absence of mRNA or the small subunit.


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