N-terminal deletion effects of human survivin on dimerization and binding to Smac/DIABLO in vitro.
Survivin, as an apoptosis suppressor, exists as a homodimer interfacing at the N-terminal portion (residues 6-13) of its baculovirus IAP repeat (BIR) domain and a linker segment (residues 89-102). Here we expressed full-length human Survivin (SurF) and a series of its mutants, SurΔN7, SurΔN13, and SurΔN18 with significant truncations of the N-terminus, all of which could still dimerize in solution. Single-molecule force spectroscopy (SMFS) was used to quantitate the unbinding forces of full-length and the mutant homodimers and revealed that the N-terminal residues up to Arg18 were not essential for dimerization. Meanwhile, the binding of SurΔN7 to Smac/DIABLO determined by ELISA was as efficient as the wild-type, but that of SurΔN13 was significantly reduced, and that of SurΔN18 was completely lost. Together, these findings provide direct evidence that the N-terminal sequence of Survivin is not critical for dimer formation but may contribute to correct folding and function of BIR.
State Key Laboratory for Supramolecular Structure and Materials, Jilin University, No. 2699, Qianjin Street, Changchun 130012 China.
Yang
Y
Gao
Huafei
H
Zhang
Min
M
Zhang
Haihong
H
Zhang
Xianghui
X
Yu
Wei
W
Kong
Xiao
X
Zha
Yuqing
Y
Wu
D051017:Apoptosis Regulatory Proteins; D002942:Circular Dichroism; D019281:Dimerization; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry*; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D000077022:Survivin
D051017:Apoptosis Regulatory Proteins; C107489:BIRC5 protein, human; C412403:DIABLO protein, human; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D000077022:Survivin