BOVINE SEMINAL RIBONUCLEASE - STRUCTURE AT 1.9-ANGSTROM RESOLUTION

Citation
L. Mazzarella et al., BOVINE SEMINAL RIBONUCLEASE - STRUCTURE AT 1.9-ANGSTROM RESOLUTION, Acta crystallographica. Section D, Biological crystallography, 49, 1993, pp. 389-402
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Crystallography,Biology,"Pharmacology & Pharmacy
ISSN journal
0907-4449
Volume
49
Year of publication
1993
Part
4
Pages
389 - 402
Database
ISI
SICI code
0907-4449(1993)49:<389:BSR-SA>2.0.ZU;2-C
Abstract
The crystal structure of bovine seminal ribonuclease, a homodimeric en zyme closely related to pancreatic ribonuclease, has been refined at a normal resolution of 1.9 angstrom employing data collected on an elec tronic area detector. The final model consists of two chains containin g 1990 non-H atoms, seven sulfate anions and 113 water molecules per a symmetric unit. The unit-cell parameters are a = 36.5 (1), b = 66.7 (1 ) and c = 107.5 (2) angstrom, space group P22(1)2(1). The R factor is 0.177 for 16 492 reflections in the resolution range 6.0-1.9 angstrom and the deviations from ideal values of bond lengths and bond angles a re 0.020 angstrom and 3.7-degrees, respectively. The molecule is forme d by two pancreatic like chains, which have their N-terminal segments interchanged so that each active site is formed by residues from both subunits. The two chains are related by a non-crystallographic twofold symmetry and are covalently linked by two consecutive disulfide bridg es, which form an unusual sixteen-membered ring across the dimer inter face. The deviations from the molecular symmetry, the hydration shell and the sulfate-binding sites are also discussed in relation to the kn own structure of the pancreatic enzyme.