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| | {{STRUCTURE_2rnt| PDB=2rnt | SCENE= }} | | {{STRUCTURE_2rnt| PDB=2rnt | SCENE= }} |
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| - | '''THREE-DIMENSIONAL STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH GUANYLYL-2(PRIME),5(PRIME)-GUANOSINE AT 1.8 ANGSTROMS RESOLUTION'''
| + | ===THREE-DIMENSIONAL STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH GUANYLYL-2(PRIME),5(PRIME)-GUANOSINE AT 1.8 ANGSTROMS RESOLUTION=== |
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| - | ==Overview==
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| - | The enzyme ribonuclease T1 (RNase T1) isolated from Aspergillus oryzae was cocrystallized with the specific inhibitor guanylyl-2',5'-guanosine (2',5'-GpG) and the structure refined by the stereochemically restrained least-squares refinement method to a crystallographic R-factor of 14.9% for X-ray data above 3 sigma in the resolution range 6 to 1.8 A. The refined model consists of 781 protein atoms, 43 inhibitor atoms in a major site and 29 inhibitor atoms in a minor site, 107 water oxygen atoms, and a metal site assigned as Ca. At the end of the refinement, the orientation of His, Asn and Gln side-chains was reinterpreted on the basis of two-dimensional nuclear magnetic resonance data. The crystal packing and enzyme conformation of the RNase T1/2',5'-GpG complex and of the near-isomorphous RNase T1/2'-GMP complex are comparable. The root-mean-square deviation is 0.73 A between equivalent protein atoms. Differences in the unit cell dimensions are mainly due to the bound inhibitor. The 5'-terminal guanine of 2',5'-GpG binds to RNase T1 in much the same way as in the 2'-GMP complex. In contrast, the hydrogen bonds between the catalytic center and the phosphate group are different and the 3'-terminal guanine forms no hydrogen bonds with the enzyme. This poor binding is reflected in a 2-fold disorder of 2',5'-GpG (except the 5'-terminal guanine), which originates from differences in the pucker of the 5'-terminal ribose. The pucker is C2'-exo for the major site (2/3 occupancy) and C1'-endo for the minor site (1/3 occupancy). The orientation of the major site is stabilized through stacking interactions between the 3'-terminal guanine and His92, an amino acid necessary for catalysis. This might explain the high inhibition rate observed for 2',5'-GpG, which exceeds that of all other inhibitors of type 2',5'-GpN. On the basis of distance criteria, one solvent peak in the electron density was identified as metal ion, probably Ca2+. The ion is co-ordinated by the two Asp15 carboxylate oxygen atoms and by six water molecules. The co-ordination polyhedron displays approximate 4m2 symmetry. | + | The line below this paragraph, {{ABSTRACT_PUBMED_2541256}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 2541256 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_2541256}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Maslowska, M.]] | | [[Category: Maslowska, M.]] |
| | [[Category: Saenger, W.]] | | [[Category: Saenger, W.]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 17:13:56 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 6 00:59:05 2008'' |
Revision as of 21:59, 5 July 2008
Template:STRUCTURE 2rnt
THREE-DIMENSIONAL STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH GUANYLYL-2(PRIME),5(PRIME)-GUANOSINE AT 1.8 ANGSTROMS RESOLUTION
Template:ABSTRACT PUBMED 2541256
About this Structure
2RNT is a Single protein structure of sequence from Aspergillus oryzae. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of ribonuclease T1 complexed with guanylyl-2',5'-guanosine at 1.8 A resolution., Koepke J, Maslowska M, Heinemann U, Saenger W, J Mol Biol. 1989 Apr 5;206(3):475-88. PMID:2541256
Page seeded by OCA on Sun Jul 6 00:59:05 2008
