8rnt
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STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH ZINC(II) AT 1.8 ANGSTROMS RESOLUTION: A ZN2+.6H2O.CARBOXYLATE CLATHRATE
OverviewOverview
In order to study the inhibitory effect of Zn2+ on ribonuclease T1 [RNase, T1; Itaya & Inoue (1982). Biochem. J. 207, 357-362], the enzyme was, cocrystallized with 2 mM Zn2+, pH 5.2, from a solution containing 55%, (v/v) 2-methyl-2,4-pentanediol. The crystals are orthorhombic, P2(1)2(1)2(1), a = 48.71 (1), b = 46.51 (1), c = 41.14 (1) A, Z = 4, V =, 93203 A3. The crystal structure was determined by molecular replacement, and refined by restrained least-squares methods based on Fhkl for 8291, unique reflections with Fo greater than or equal to 1 sigma (Fo) in the, resolution range 10 to 1.8 A and converged at a crystallographic R factor, of 0.140. The Zn2+ is not bonded to the active site of RNase T1, probably, because the His40 and His92 side chains are protonated. Zn2+ occupies the, same site as Ca2+ in a series of crystal structures of free and, nucleotide-complexed RNase T1. It is coordinated to Asp15 carboxylate and, to six water molecules forming a dodecahedron of square antiprismatic, form. The Zn2+...O distances are approximately 2.5 A, suggesting that Zn2+, is clathrated and not coordinated, which would require distances of 2.0 A.
About this StructureAbout this Structure
8RNT is a Single protein structure of sequence from Aspergillus oryzae with ZN as ligand. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
ReferenceReference
Structure of ribonuclease T1 complexed with zinc(II) at 1.8 A resolution: a Zn2+.6H2O.carboxylate clathrate., Ding J, Choe HW, Granzin J, Saenger W, Acta Crystallogr B. 1992 Apr 1;48 ( Pt 2):185-91. PMID:1515106
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