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Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes.
Author:	Druzina, Zhanna.
Description:	244 p.
Notes:	Source: Dissertation Abstracts International, Volume: 64-10, Section: B, page: 4913.
Notes:	Supervisor: Barry S. Cooperman.
Contained By:	Dissertation Abstracts International64-10B.
Subject:	Chemistry, Biochemistry.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3109172
ISBN:	0496567152

Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes.
Druzina, Zhanna.

Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes. [electronic resource] - 244 p.

Source: Dissertation Abstracts International, Volume: 64-10, Section: B, page: 4913.

Thesis (Ph.D.)--University of Pennsylvania, 2003.

By using photolabile oligonucleotide probes (PHONTs) complementary to peptidyl transferase center of 23S rRNA we demonstrated that 23S rRNA nts 2404--2406 and 2411 can move within 19 A from nts 2252/2253. These nucleotides are 65--72 A apart according to the crystal structure, implying that these regions are mobile.

ISBN: 0496567152Subjects--Topical Terms:

226900
Chemistry, Biochemistry.

Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes.
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245 1 0 $a Identifying conformationally labile functional regions of Escherichia coli ribosomes using chemical probes. $h [electronic resource]
300 $a 244 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-10, Section: B, page: 4913.
500 $a Supervisor: Barry S. Cooperman.
502 $a Thesis (Ph.D.)--University of Pennsylvania, 2003.
520 # $a By using photolabile oligonucleotide probes (PHONTs) complementary to peptidyl transferase center of 23S rRNA we demonstrated that 23S rRNA nts 2404--2406 and 2411 can move within 19 A from nts 2252/2253. These nucleotides are 65--72 A apart according to the crystal structure, implying that these regions are mobile.
520 # $a Employing chemical footprinting we identified highly flexible regions of 23S rRNA that are close to the binding sites of proteins L1, L11 and to flexible helix 69. The flexibility of these regions is also suggested by X-ray crystallography.
520 # $a Photolabile derivatives of anticodon stem-loop tRNA analog (Ph-ASLs), corresponding to positions 27--43 of E. coli tRNA Phe, were used to probe interactions between the ribosomes and the anticodon loop placed in the P or E sites. The Ph-ASLs carry 4-thiouridine, capable of forming zero-length photocrosslinks to rRNA, in positions adjacent to either the 5'- or 3'-anticodon nucleotides (position 33 and 37 in tRNAPhe, respectively). These Ph-ASLs bind to and crosslink from the P or E sites of 70S subunits in a competitive manner with respect to tRNAPhe. Ph-ASL bound to the E-site in mRNA-independent manner is situated in close proximity to P-site bound tRNA, and E-site binding of Ph-ASL requires the presence of P-site bound tRNA. These results lead to a proposal of a third exit site, E1 ', closer to E1 than to E2.
520 # $a The Ph-ASLs crosslinks provide direct evidence for large scale movement of the decoding portion of helix 44 of 16S rRNA in the same direction as tRNA translocation. They also demonstrate that the 3'-terminus of 16S rRNA is flexible and is capable of folding back into the decoding center even when the 30S subunit is a part of 70S ribosomes.
520 # $a The ribosome, a large ribonucleoprotein complex responsible for protein synthesis, has three or more tRNA binding sites: A (aminoacyl-tRNA), P (peptidyl-tRNA) and E (exit). For the latter, two locations have been proposed, E1 and E2. It has been demonstrated that ribosome undergoes large conformational changes during translation that have not been accessible by X-ray crystallography. We employ photoaffinity labeling and chemical footprinting in identifying flexible and functional regions of Escherichia coli ribosomes.
590 $a School code: 0175.
650 # 0 $a Chemistry, Biochemistry. $3 226900
710 0 # $a University of Pennsylvania. $3 212781
773 0 # $g 64-10B. $t Dissertation Abstracts International
790 $a 0175
790 1 0 $a Cooperman, Barry S., $e advisor
791 $a Ph.D.
792 $a 2003
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