title: Thermal dependency of RAG1 self-association properties.
abstract: BACKGROUND
  Functional immunoglobulin and T cell receptor genes are produced in developing lymphocytes by V(D)J recombination. The initial site-specific DNA cleavage steps in this process are catalyzed by the V(D)J recombinase, consisting of RAG1 and RAG2, which is directed to appropriate DNA cleavage sites by recognition of the conserved recombination signal sequence (RSS). RAG1 contains both the active site and the RSS binding domains, although RAG2 is also required for DNA cleavage activity. An understanding of the physicochemical properties of the RAG proteins, their association, and their interaction with the RSS is not yet well developed.
  
  
  RESULTS
  Here, we further our investigations into the self-association properties of RAG1 by demonstrating that despite the presence of multiple RAG1 oligomers, only the dimeric form maintains the ability to interact with RAG2 and the RSS. However, facile aggregation of the dimeric form at physiological temperature may render this protein inactive in the absence of RAG2. Upon addition of RAG2 at 37 degrees C, the preferentially stabilized V(D)J recombinase:RSS complex contains a single dimer of RAG1.
  
  
  CONCLUSIONS
  Together these results confirm that the functional form of RAG1 in V(D)J recombination is in the dimeric state, and that its stability under physiological conditions likely requires complex formation with RAG2. Additionally, in future structural and functional studies of RAG1, it will be important to take into account the temperature-dependent self-association properties of RAG1 described in this study.
authors.affiliation: Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA. pallabi.de@umassmed.edu
authors.forename: Pallabi
authors.initials: P
authors.lastname: De
authors.forename: Shuying
authors.initials: S
authors.lastname: Zhao
authors.forename: Lori M
authors.initials: LM
authors.lastname: Gwyn
authors.forename: Leann J
authors.initials: LJ
authors.lastname: Godderz
authors.forename: Mandy M
authors.initials: MM
authors.lastname: Peak
authors.forename: Karla K
authors.initials: KK
authors.lastname: Rodgers
mesh_terms: D002384:Catalysis; D053837:DNA Cleavage; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D013379:Substrate Specificity; D013696:Temperature; D045567:VDJ Recombinases / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C064658:RAG-1 protein; D045567:VDJ Recombinases