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1h8x

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{{STRUCTURE_1h8x| PDB=1h8x | SCENE= }}
{{STRUCTURE_1h8x| PDB=1h8x | SCENE= }}
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'''DOMAIN-SWAPPED DIMER OF A HUMAN PANCREATIC RIBONUCLEASE VARIANT'''
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===DOMAIN-SWAPPED DIMER OF A HUMAN PANCREATIC RIBONUCLEASE VARIANT===
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==Overview==
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BACKGROUND: Domain swapping has been proposed as a mechanism that explains the evolution from monomeric to oligomeric proteins. Bovine and human pancreatic ribonucleases are monomers with no biological properties other than their RNA cleavage ability. In contrast, the closely related bovine seminal ribonuclease is a natural domain-swapped dimer that has special biological properties, such as cytotoxicity to tumour cells. Several recombinant ribonuclease variants are domain-swapped dimers, but a structure of this kind has not yet been reported for the human enzyme. RESULTS: The crystal structure at 2 A resolution of an engineered ribonuclease variant called PM8 reveals a new kind of domain-swapped dimer, based on the change of N-terminal domains between the two subunits. The swapping is fastened at both hinge peptides by the newly introduced Gln101, involved in two intermolecular hydrogen bonds and in a stacking interaction between residues of different chains. Two antiparallel salt bridges and water-mediated hydrogen bonds complete a new interface between subunits, while the hinge loop becomes organized in a 3(10) helix structure. CONCLUSIONS: Proteins capable of domain swapping may quickly evolve toward an oligomeric form. As shown in the present structure, a single residue substitution reinforces the quaternary structure by forming an open interface. An evolutionary advantage derived from the new oligomeric state will fix the mutation and favour others, leading to a more extended complementary dimerization surface, until domain swapping is no longer necessary for dimer formation. The newly engineered swapped dimer reported here follows this hypothetical pathway for the rapid evolution of proteins.
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(as it appears on PubMed at http://www.pubmed.gov), where 11591351 is the PubMed ID number.
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{{ABSTRACT_PUBMED_11591351}}
==About this Structure==
==About this Structure==
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[[Category: Ribonuclease]]
[[Category: Ribonuclease]]
[[Category: Rnase]]
[[Category: Rnase]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:34:54 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 06:50:59 2008''

Revision as of 03:51, 1 July 2008

Image:1h8x.png

Template:STRUCTURE 1h8x

DOMAIN-SWAPPED DIMER OF A HUMAN PANCREATIC RIBONUCLEASE VARIANT

Template:ABSTRACT PUBMED 11591351

About this Structure

1H8X is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

The structure of an engineered domain-swapped ribonuclease dimer and its implications for the evolution of proteins toward oligomerization., Canals A, Pous J, Guasch A, Benito A, Ribo M, Vilanova M, Coll M, Structure. 2001 Oct;9(10):967-76. PMID:11591351

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