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chemistry colloquia

Monday 23 September
Gerhard M.J. Schmidt Lecture Hall 11:00
Ribosomal decoding, tRNA modifications and human disease Prof. Eric Westhof [Info]

Ribosomal decoding, tRNA modifications and human disease

Decoding during ribosomal translation occurs through complex and interdependent molecular recognition networks between mRNA, tRNA, and rRNA. Among those, the stability of codon-anticodon triplets, the fold of the tRNA anticodon hairpin, the modified nucleotides, and the interactions with rRNA bases at the decoding site cosntitute key contributors. On the basis of biochemical and genetic data in the literature, coupled with many crystal structures of fully active ribosomes, nucleotide modifications at positions 34 and 37 of the anticodon loop are now understood molecularly. Both pre-organize the anticodon loop for efficient mRNA binding. The modifications at 37 stabilize AU-rich codon-anticodon pairs and maintain the coding frame. The modifications at 34 help to avoid miscoding and allow to decode purine-ending codons in split codon boxes by promoting base pairing that can be accommodated within the structural constraints of the ribosomal grip at the decoding site. Depending on the codon box, 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 genetic code is not translated identically and differences exist not only between 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 homeostasis. Examples of mutations leading to specific human diseases in some of those enzymes will be described. Institut de Biologie Moléculaire et Cellulaire Centre National de la Recherche Scientifique
Monday 28 October
Gerhard M.J. Schmidt Lecture Hall 11:00
Chemistry colloquium Prof. Eiichi Nakamura [Info]

Chemistry colloquium

University of Tokyo
Monday 25 November
Gerhard M.J. Schmidt Lecture Hall 11:00
Chemistry colloquium Dr. Ron Diskin [Info]

Chemistry colloquium

Dept. of Structural Biology, WIS
Monday 09 December
Gerhard M.J. Schmidt Lecture Hall 11:00
Chemistry colloquium Dr. Emmanuel Levy [Info]

Chemistry colloquium

Dept. of Structural Biology, WIS
Monday 16 December
Gerhard M.J. Schmidt Lecture Hall 11:00
Chemistry colloquium Prof. Thuc-Quyen Nguyen [Info]

Chemistry colloquium

University of California, Santa Barbara