title: Characterization of a core fragment of the rhesus monkey TRIM5α protein.
abstract: BACKGROUND
  Like all tripartite motif (TRIM) proteins, the retroviral restriction factor TRIM5α consists of RING, B-box 2 and coiled-coil domains, with a C-terminal B30.2(SPRY) domain. Although structures have been determined for some individual TRIM domains, the structure of an intact TRIM protein is unknown.
  
  
  RESULTS
  Here, we express and characterize a protease-resistant 29-kD core fragment containing the B-box 2, coiled coil and adjacent linker (L2) region of TRIM5α. This BCCL2 protein formed dimers and higher-order oligomers in solution. Approximately 40% of the BCCL2 secondary structure consisted of alpha helices. Partial loss of alpha-helical content and dissociation of dimers occurred at 42°C, with the residual alpha helices remaining stable up to 80°C.
  
  
  CONCLUSIONS
  These results indicate that the B-box 2, coiled-coil and linker 2 regions of TRIM5α form a core dimerization motif that exhibits a high level of alpha-helical content.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Alak K
authors.initials: AK
authors.lastname: Kar
authors.forename: Youdong
authors.initials: Y
authors.lastname: Mao
authors.forename: Gregory
authors.initials: G
authors.lastname: Bird
authors.forename: Loren
authors.initials: L
authors.lastname: Walensky
authors.forename: Joseph
authors.initials: J
authors.lastname: Sodroski
mesh_terms: D000818:Animals; D019281:Dimerization; D004926:Escherichia coli; D008253:Macaca mulatta; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary / Q000235:genetics*; D011506:Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature; D044767:Ubiquitin-Protein Ligases; D015032:Zinc / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D011506:Proteins; D011993:Recombinant Fusion Proteins; C482587:TRIM5(alpha) protein, rhesus monkey; D044767:Ubiquitin-Protein Ligases; D015032:Zinc