Article
Self-association and conformational properties of RAG1: implications for formation of the V(D)J recombinase

Authors: Godderz L.J.; Rahman N.S.; Risinger G.M.; Arbuckle J.L.; Rodgers K.K.

Source: Nucleic Acids Research, Volume 31, Number 7, 1 April 2003 , pp. 2014-2023(10)

Publisher: Oxford University Press

Buy & download fulltext article:

The full text is free.

View now:

PDF 256.3kb

Abstract:

RAG1 and RAG2 catalyze the initial DNA cleavage steps in V(D)J recombination. Fundamental properties of these proteins remain largely unknown. Here, self-association and conformational properties of murine core RAG1 (residues 384–1008) were examined. As determined by multi-angle laser light scattering measurements, the molecular masses of two predominant core RAG1 species corresponded to dimeric and tetrameric states. Similar results were obtained using a RAG1 fragment containing residues 265–1008, indicating that a non-core portion of RAG1 does not alter the oligomerization states observed for the core region. The fraction of core RAG1 in the tetrameric state increased significantly at lower ionic strengths (0.2 versus 0.5 M NaCl), indicating that this oligomeric form may factor into the physiological function of RAG1. In addition, the secondary structural content of core RAG1, obtained by circular dichroism spectroscopy, demonstrated a significant dependence on ionic strength with a 26% increase in alpha -helical content from 0.2 to 1.0 M NaCl. Together, these results indicate that structural and oligomerization properties of core RAG1 are strongly dependent on electrostatic interactions. Furthermore, the secondary structure of core RAG1 changes upon binding to DNA, with larger increases in alpha -helical content upon binding to the recombination signal sequence (RSS) as compared with non-sequence-specific DNA. As shown by electrophoretic mobility shift assays, higher order oligomeric forms of core RAG1 bound to the canonical RSS. Furthermore, core RAG2 (residues 1–387) formed complexes with multimeric RAG1 species bound to a single RSS, providing additional support for the physiological relevance of higher order oligomeric states of RAG1.

Document Type: Original article

Affiliations: Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA

Publication date: 2003-04-01

More about this publication?

Nucleic Acids Research (NAR) is a fully Open Access journal, providing rapid publication of leading edge research into the nucleic acids under the following categories: chemistry, computational biology, genomics, molecular biology, nucleic acid enzymes, RNA and structural biology. There is a Survey and Summary section, and methods papers are published
in NAR Methods Online. Each year the first issue is devoted to biological databases, and a later issue to relevant web-based software resources.