11ba
BINDING OF A SUBSTRATE ANALOGUE TO A DOMAIN SWAPPING PROTEIN IN THE COMPLEX OF BOVINE SEMINAL RIBONUCLEASE WITH URIDYLYL-2',5'-ADENOSINE
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OverviewOverview
Bovine seminal ribonuclease (BS-RNase) is a unique member of the, pancreatic-like ribonuclease superfamily. The native enzyme is a mixture, of two dimeric forms with distinct structural features. The most abundant, form is characterized by the swapping of N-terminal fragments. In this, paper, the crystal structure of the complex between the swapping dimer and, uridylyl(2',5')adenosine is reported at 2.06 A resolution. The refined, model has a crystallographic R-factor of 0.184 and good stereochemistry., The quality of the electron density maps enables the structure of both the, inhibitor and active site residues to be unambiguously determined. The, overall architecture of the active site is similar to that of RNase A. The, dinucleotide adopts an extended conformation with the pyrimidine and, purine base interacting with Thr45 and Asn71, respectively. Several, residues (Gln11, His12, Lys41, His119, and Phe120) bind the oxygens of the, phosphate group. The structural similarity of the active sites of BS-RNase, and RNase A includes some specific water molecules believed to be relevant, to catalytic activity. Upon binding of the dinucleotide, small but, significant modifications of the tertiary and quaternary structure of the, protein are observed. The ensuing correlation of these modifications with, the catalytic activity of the enzyme is discussed.
About this StructureAbout this Structure
11BA is a Single protein structure of sequence from Bos taurus with SO4 and UPA as ligands. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.
ReferenceReference
Binding of a substrate analog to a domain swapping protein: X-ray structure of the complex of bovine seminal ribonuclease with uridylyl(2',5')adenosine., Vitagliano L, Adinolfi S, Riccio A, Sica F, Zagari A, Mazzarella L, Protein Sci. 1998 Aug;7(8):1691-9. PMID:10082366
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