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Updated: Sep 28, 2026

Method for Efficient Refolding and Purification of Chemoreceptor Ligand Binding Domain
Published on: December 12, 2017
Engineering the refolding pathway and the quaternary structure of seminal ribonuclease by newly introduced disulfide
Aniello Russo1, Antonella Antignani, Concetta Giancola
1Department of Life Sciences, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
Abstract:
Seminal RNase (BS-RNase), a ribonuclease from bovine seminal vesicles, is a homodimeric enzyme with a strong cytotoxic activity selective for tumor cells. It displays the unusual structural feature of existing in solution as an equilibrium mixture of two quaternary isoforms. The major one is characterized by the swap between subunits of their N-terminal ends, whereas the minor isoform shows no swap. The tendency of the two isolated isoforms to interconvert into each other has so far made it difficult to attribute the functional properties of BS-RNase to either isoform. Herein, molecular modeling and site-directed mutagenesis were used to engineer the refolding pathway of BS-RNase and obtain a stable variant of its non-swapping isoform. The protein was engineered with two extra disulfide bridges linking the N-terminal helix of each subunit to the main body of the same subunit. Purified as an active enzyme, the BS-RNase variant was found to be very resistant to thermal denaturation. Its functional characterization revealed that the lack of swapping has a negative effect on the cytotoxic activity of BS-RNase.
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