1m5k
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(New page: 200px<br /> <applet load="1m5k" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m5k, resolution 2.40Å" /> '''CRYSTAL STRUCTURE O...)
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Revision as of 16:01, 12 November 2007
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CRYSTAL STRUCTURE OF A HAIRPIN RIBOZYME IN THE CATALYTICALLY-ACTIVE CONFORMATION
Overview
The hairpin ribozyme catalyses sequence-specific cleavage of RNA. The, active site of this natural RNA results from the docking of two irregular, helices: stems A and B. One strand of stem A harbours the scissile bond., The 2.4 A resolution structure of a hairpin ribozyme-inhibitor complex, reveals that the ribozyme aligns the 2'-OH nucleophile and the 5'-oxo, leaving group by twisting apart the nucleotides that flank the scissile, phosphate. The base of the nucleotide preceding the cleavage site is, stacked within stem A; the next nucleotide, a conserved guanine, is, extruded from stem A and accommodated by a highly complementary pocket in, the minor groove of stem B. Metal ions are absent from the active site., The bases of four conserved purines are positioned potentially to serve as, acid-base catalysts. This is the first structure determination of a fully, assembled ribozyme active site that catalyses a phosphodiester cleavage, without recourse to metal ions.
About this Structure
1M5K is a Single protein structure of sequence from Homo sapiens with CA, CL, IOD and CH3 as ligands. This structure superseeds the now removed PDB entry 1HP6. Full crystallographic information is available from OCA.
Reference
Crystal structure of a hairpin ribozyme-inhibitor complex with implications for catalysis., Rupert PB, Ferre-D'Amare AR, Nature. 2001 Apr 12;410(6830):780-6. PMID:11298439
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