2z2u
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(New page: 200px<br /><applet load="2z2u" size="350" color="white" frame="true" align="right" spinBox="true" caption="2z2u, resolution 2.40Å" /> '''Crystal structure of...)
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Revision as of 09:04, 23 January 2008
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Crystal structure of archaeal TYW1
Overview
Wyosine and its derivatives, such as wybutosine, found in eukaryotic and, archaeal tRNAs, are tricyclic hypermodified nucleosides. In eukaryotes, wybutosine exists exclusively in position 37, 3'-adjacent to the, anticodon, of tRNA(Phe), where it ensures correct translation by, stabilizing the codon-anticodon base-pairing during the ribosomal decoding, process. Recent studies revealed that the wyosine biosynthetic pathway, consists of multistep enzymatic reactions starting from a guanosine, residue. Among these steps, TYW1 catalyzes the second step to form the, tricyclic ring structure, by cyclizing N(1)-methylguanosine. In this, study, we solved the crystal structure of TYW1 from Methanocaldococcus, jannaschii at 2.4 A resolution. TYW1 assumes an incomplete TIM barrel with, (alpha/beta)(6) topology, which closely resembles the reported structures, of radical SAM enzymes. Hence, TYW1 was considered to catalyze the, cyclization reaction by utilizing the radical intermediate. Comparison, with other radical SAM enzymes allowed us to build a model structure, complexed with S-adenosylmethionine and two [4Fe-4S] clusters. Mutational, analyses in yeast supported the validity of this complex model structure, which provides a structural insight into the radical reaction involving, two [4Fe-4S] clusters to create a complex tricyclic base.
About this Structure
2Z2U is a Single protein structure of sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA.
Reference
Crystal Structure of the Radical SAM Enzyme Catalyzing Tricyclic Modified Base Formation in tRNA., Suzuki Y, Noma A, Suzuki T, Senda M, Senda T, Ishitani R, Nureki O, J Mol Biol. 2007 Oct 5;372(5):1204-14. Epub 2007 Jul 26. PMID:17727881
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