1y92

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spinqualitylabelsall models 1y92, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of the P19A/N67D Variant Of Bovine seminal Ribonuclease

Overview

Bovine seminal ribonuclease (BS-RNase) is a covalent homodimeric enzyme, homologous to pancreatic ribonuclease (RNase A), endowed with a number of, special biological functions. It is isolated as an equilibrium mixture of, swapped (MxM) and unswapped (M=M) dimers. The interchanged N termini are, hinged on the main bodies through the peptide 16-22, which changes, conformation in the two isomers. At variance with other proteins, domain, swapping in BS-RNase involves two dimers having a similar and highly, constrained quaternary association, mainly dictated by two interchain, disulfide bonds. This provides the opportunity to study the intrinsic, ability to swap as a function of the hinge sequence, without additional, effects arising from dissociation or quaternary structure modifications., Two variants, having Pro19 or the whole sequence of the hinge replaced by, the corresponding residues of RNase A, show equilibrium and kinetic, parameters of the swapping similar to those of the parent protein. In, comparison, the x-ray structures of MxM indicate, within a substantial, constancy of the quaternary association, a greater mobility of the hinge, residues. The relative insensitivity of the swapping tendency to the, substitutions in the hinge region, and in particular to the replacement of, Pro19 by Ala, contrasts with the results obtained for other swapped, proteins and can be rationalized in terms of the unique features of the, seminal enzyme. Moreover, the results indirectly lend credit to the, hypothesis that the major role of Pro19 resides in directing the assembly, of the non-covalent dimer, the species produced by selective reduction of, the interchain disulfides and considered responsible for the special, biological functions of BS-RNase.

About this Structure

1Y92 is a Single protein structure of sequence from Bos taurus. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.

Reference

The role of the hinge loop in domain swapping. The special case of bovine seminal ribonuclease., Picone D, Di Fiore A, Ercole C, Franzese M, Sica F, Tomaselli S, Mazzarella L, J Biol Chem. 2005 Apr 8;280(14):13771-8. Epub 2005 Jan 12. PMID:15647261

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