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SUMMARY:tRNA Modifications and Decoding Errors - Professor Eric Westhof (I
 nstitut de Biologie Moléculaire et Cellulaire du CNRS\, Université de St
 rasbourg)
DTSTART:20190220T160000Z
DTEND:20190220T180000Z
UID:TALK120046@talks.cam.ac.uk
CONTACT:Mairi Kilkenny
DESCRIPTION:Ribosomal translation occurs through complex molecular interac
 tion networks between mRNA\, tRNA\, and rRNA. Among those\, the stability 
 of codon-anticodon triplets\, the conformation of the anticodon stem-loop 
 of tRNA\, the modified nucleotides\, and the interactions with bases of rR
 NA at the decoding site form key contributors. Because the cellular activi
 ties of several enzymatic complexes are required for the maintenance of ac
 tive ribosomes as well as of the pool of matured and modified tRNAs\, ribo
 somal translation is intimately integrated within the biochemical\, metabo
 lic and cellular evolution processes in extant organisms. On the basis of 
 many crystal structures of fully active ribosomes\, nucleotide modificatio
 ns\, especially at positions 34 and 37 of the anticodon loop\, are now bet
 ter understood molecularly. Depending on the codon box\, the modifications
  stabilize AU-rich codon-anticodon pairs and maintain the coding frame. Th
 ey also contribute to the decoding of purine-ending codons in split codon 
 boxes and help to avoid miscoding. Overall\, the tRNA modifications allow 
 for diversity in codon usage depending on genomic GC content as well as on
  the number and types of isoacceptor tRNAs. Although universal\, the genet
 ic code is not translated identically and differences exist not only betwe
 en organisms in the three kingdoms of life but also between cellular types
 . To decipher diversely but efficiently the genetic code\, cells developed
  sophisticated arrays between tRNA pools and tRNA modifications\, anchored
  in the cellular metabolic enzymatic pathways and guaranteeing protein hom
 eostasis. Examples of mutations that lead to specific human diseases in so
 me of those enzymes will be described.
LOCATION:Jean Thomas Lecture Theatre\, Sanger Biochemistry Building
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