Unique structural features of a BCL-2 family protein CED-9 and biophysical characterization of CED-9/EGL-1 interactions.
The interactions between B-cell lymphoma 2 (BCL-2) family members are known to be mediated through the binding of the BH3 domain of a proapoptotic member to the BH3-binding groove of an antiapoptotic member. We determined the crystal structure of antiapoptotic CED-9, which reveals a unique C-terminal helix altering the common BH3-binding region. A coexpression system to produce CED-9 in complex with proapoptotic EGL-1 enabled us to show that the binding of EGL-1 to CED-9 is extremely stable, raising the melting temperature (T(M)) of CED-9 by 25 degrees C, and that the binding surface of CED-9 extends beyond the BH3-binding region and reaches the BH4 domain. Consistently, the T(M) and a 1H-15N correlation NMR spectrum of CED-9 in complex with EGL-1 are drastically different from those of CED-9 in complex with the EGL-1 BH3 peptide. The data suggest that the recognition between other BCL-2 family members may also involve much wider protein surfaces than is previously thought.
Woo
J-S
JS
Department of Life Science, Center for Biomolecular Recognition and Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Kyungbuk 790-784, Korea.
Jung
J-S
JS
Ha
N-C
NC
Shin
J
J
Kim
K-H
KH
Lee
W
W
Oh
B-H
BH
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000378:metabolism*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
D051017:Apoptosis Regulatory Proteins; D029742:Caenorhabditis elegans Proteins; C087233:Ced-9 protein, C elegans; C112486:EGL-1 protein, C elegans; D010455:Peptides; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D012097:Repressor Proteins