1ipa
CRYSTAL STRUCTURE OF RNA 2'-O RIBOSE METHYLTRANSFERASE
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OverviewOverview
Knots in polypeptide chains have been found in very few proteins. Only two, proteins are considered to have a shallow 'trefoil' knot, which tucks a, few residues at one end of the chain through a loop exposed on the protein, surface. Recently, another protein was found by a mathematical algorithm, to have a deep 'figure-of-eight' knot which had not been visually, identified. In the present study, the crystal structure of a hypothetical, RNA 2'-O-ribose methyltransferase from Thermus thermophilus (RrmA) was, determined at 2.4 A resolution and a deep trefoil knot was found for the, first time. The present knot is formed by the threading of a 44-residue, polypeptide chain through a 41-residue loop and is better defined than the, previously reported knots. Two of the three catalytic residues conserved, in the 2'-O-ribose methyltransferase family are located in the knotting, loop and in the knotted carboxy-terminal chain, which is the first, observation that the enzyme active site is constructed right on the knot., On the other hand, the amino-terminal domain exhibits a geometrical, similarity to the ribosomal proteins which recognize an internal loop of, RNA.
About this StructureAbout this Structure
1IPA is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
ReferenceReference
An enzyme with a deep trefoil knot for the active-site architecture., Nureki O, Shirouzu M, Hashimoto K, Ishitani R, Terada T, Tamakoshi M, Oshima T, Chijimatsu M, Takio K, Vassylyev DG, Shibata T, Inoue Y, Kuramitsu S, Yokoyama S, Acta Crystallogr D Biol Crystallogr. 2002 Jul;58(Pt 7):1129-37. Epub 2002, Jun 20. PMID:12077432
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