1lsq
From Proteopedia
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RIBONUCLEASE A WITH ASN 67 REPLACED BY A BETA-ASPARTYL RESIDUE
Overview
The non-enzymatic deamidation of asparagine residues in proteins is a, widely occurring reaction, both in vivo and in vitro. Although the, importance of this process is commonly recognised, only little structural, information is available on it. In order to evaluate the structural, effects of this reaction in proteins, we have determined the crystal, structure of a ribonuclease A derivative in which asparagine 67 has been, replaced by an isoaspartyl residue, as a consequence of an in vitro, deamidation reaction. The overall structure of the model, refined to a, crystallographic R-factor of 0.159 at a resolution of 1.9 A, is very, similar to that of the native protein, but considerable deviations are, observed in the region delimited by the disulphide bridge 65-72. In, particular, the insertion of an extra methylene group in the main chain at, residue 67 breaks up the hydrogen bond network that makes this region, rather rigid in ribonuclease A. On the basis of the structure observed, some of the slightly but significantly different properties of this, deamidated derivative, with respect to the native enzyme, can be, explained.
About this Structure
1LSQ is a Single protein structure of sequence from Bos taurus with SO4 as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.
Reference
Deamidation in proteins: the crystal structure of bovine pancreatic ribonuclease with an isoaspartyl residue at position 67., Capasso S, Di Donato A, Esposito L, Sica F, Sorrentino G, Vitagliano L, Zagari A, Mazzarella L, J Mol Biol. 1996 Apr 5;257(3):492-6. PMID:8648618
Page seeded by OCA on Tue Nov 20 20:50:53 2007
