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34 Cyo-EM visualization of Mycobacterium 70S ribosome reveals unique structural components at the function sites

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Title 34 Cyo-EM visualization of Mycobacterium 70S ribosome reveals unique structural components at the function sites
 
Creator Shasmal, Manidip
Sengupta , Jayati
 
Subject Structural Biology & Bioinformatics
 
Description The 3D structures of prokaryotic and eukaryotic ribosomes by crystallography and electron microscopy have revealed that they share an evolutionarily conserved core (Schmeing & Ramakrishnan, 2009), but each of the ribosomes contains its own set of specific proteins (or extensions of conserved proteins) and expansion segments of rRNAs (Melnikov et al., 2012). How these differences correlate to function still remains largely unknown. A 3D cryo-EM map of the 70S ribosome from Mycobacterium smegmatis (Msm70S) unveiled striking new structural features (Shasmal & Sengupta, 2012). The core of the Msm70S shows overall similarity with the core of the Escherichia coli 70S ribosome while containing additional mass in the periphery and solvent exposed sides. Some of the Mycobacterium ribosomal proteins are significantly bigger as compared to the E. coli counter parts. The rRNAs also contain extra helices, also revealed by their secondary structures. Most of the additional density of the Msm70S can be largely attributed to the extra helices present in the rRNAs, and extra domains of homologous proteins. One of the most notable features appears in the large subunit near L1 stalk as a structure forming a long helix with its upper end located in the vicinity of the mRNA exit channel (which we term the ‘steeple’). We propose that the prominent helical structure in mycobacterium 23S rRNA participates in modulating different steps of translation, especially the E site tRNA exit mechanism and propagation of mRNA 5′ end
 
Date 2013
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/1932/1/JOURNAL_OF_BIOMOLECULAR_STRUCTURE_%26_DYNAMICS__31___Special_Issue_SI___Supplement_1__%2C_21%2D22;2013[93].pdf
Shasmal, Manidip and Sengupta , Jayati (2013) 34 Cyo-EM visualization of Mycobacterium 70S ribosome reveals unique structural components at the function sites. Journal of Biomolecular Structure and Dynamics, 31 (supp.1). pp. 21-22.
 
Relation http://dx.doi.org/10.1080/07391102.2013.786467
http://www.eprints.iicb.res.in/1932/