2LFJ image
Deposition Date 2011-07-06
Release Date 2012-02-08
Last Version Date 2024-10-30
Entry Detail
PDB ID:
2LFJ
Keywords:
Title:
Solution structure of the monomeric derivative of BS-RNase
Biological Source:
Source Organism:
Bos taurus (Taxon ID: 9913)
Host Organism:
Method Details:
Experimental Method:
Conformers Calculated:
100
Conformers Submitted:
10
Selection Criteria:
structures with the lowest energy
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Seminal ribonuclease
Gene (Uniprot):SRN
Mutations:N67D
Chain IDs:A
Chain Length:124
Number of Molecules:1
Biological Source:Bos taurus
Ligand Molecules
Primary Citation
NMR Studies on Structure and Dynamics of the Monomeric Derivative of BS-RNase: New Insights for 3D Domain Swapping.
Plos One 7 e29076 e29076 (2012)
PMID: 22253705 DOI: 10.1371/journal.pone.0029076

Abstact

Three-dimensional domain swapping is a common phenomenon in pancreatic-like ribonucleases. In the aggregated state, these proteins acquire new biological functions, including selective cytotoxicity against tumour cells. RNase A is able to dislocate both N- and C-termini, but usually this process requires denaturing conditions. In contrast, bovine seminal ribonuclease (BS-RNase), which is a homo-dimeric protein sharing 80% of sequence identity with RNase A, occurs natively as a mixture of swapped and unswapped isoforms. The presence of two disulfides bridging the subunits, indeed, ensures a dimeric structure also to the unswapped molecule. In vitro, the two BS-RNase isoforms interconvert under physiological conditions. Since the tendency to swap is often related to the instability of the monomeric proteins, in these paper we have analysed in detail the stability in solution of the monomeric derivative of BS-RNase (mBS) by a combination of NMR studies and Molecular Dynamics Simulations. The refinement of NMR structure and relaxation data indicate a close similarity with RNase A, without any evidence of aggregation or partial opening. The high compactness of mBS structure is confirmed also by H/D exchange, urea denaturation, and TEMPOL mapping of the protein surface. The present extensive structural and dynamic investigation of (monomeric) mBS did not show any experimental evidence that could explain the known differences in swapping between BS-RNase and RNase A. Hence, we conclude that the swapping in BS-RNase must be influenced by the distinct features of the dimers, suggesting a prominent role for the interchain disulfide bridges.

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