Solution structure of the HRDC domain of human Bloom syndrome protein BLM.
Bloom syndrome is a rare genetic disorder characterized by severe growth retardation and cancer predisposition. The disease is caused by a loss of function of the Bloom syndrome protein (BLM), a member of the RecQ family of DNA helicases. Here we report on the first 3D structure of a BLM fragment, a solution structure of the C-terminal helicase-and-ribonuclease D-C-terminal (HRDC) domain from human BLM. The structure reveals unique features of BLM HRDC that are distinct from the HRDC domain of Werner syndrome protein. In particular, BLM HRDC retains many acidic residues exposed to the solvent, which makes the domain surface extensively electronegative. Consistent with this, fluorescence polarization assays showed an inability of isolated BLM HRDC to interact with DNA substrates. Analyses employing ultracentrifugation, gel-filtration, CD spectroscopy and dynamic light scattering showed that the BLM HRDC domain exists as a stable monomer in solution. The results show that BLM HRDC is a compact, robust and acidic motif which may play a distinct role apart from DNA binding.
Sato
Akiko
A
Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, Japan.
Mishima
Masaki
M
Nagai
Aki
A
Kim
Sun-Yong
SY
Ito
Yutaka
Y
Hakoshima
Toshio
T
Jee
Jun-Goo
JG
Kitano
Ken
K
D000595:Amino Acid Sequence; D001816:Bloom Syndrome / Q000235:genetics; D005090:Exodeoxyribonucleases / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D000071657:Werner Syndrome Helicase
D005090:Exodeoxyribonucleases; C097151:Bloom syndrome protein; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase