Department of Molecular Biology, College of Natural Sciences, Pusan National University, 2Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan, 46241, Republic of Korea.
Korea Nanobiotechnology Center, Pusan National University, 2,Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan, 46241, Republic of Korea.
Biochem Biophys Res Commun. 2021 Apr 9;548:39-46. doi: 10.1016/j.bbrc.2021.02.049. Epub 2021 Feb 22.
PUMA (p53-upregulated modulator of apoptosis) is localized in mitochondria and a direct target in p53-mediated apoptosis. p53 elicits mitochondrial apoptosis via transcription-dependent and independent mechanisms. p53 is known to induce apoptosis via the transcriptional induction of PUMA, which encodes proapoptotic BH3-only members of the Bcl-2 protein family. However, the transcription-independent mechanisms of human PUMA remain poorly defined. For example, it is not known whether PUMA interacts directly with the DNA binding domain (DBD: residues 92-293) of p53 in vitro. Here, the structure of the complex between the DBD of p53 and PUMA peptide was elucidated by X-ray crystallography. Isothermal titration calorimetry showed that PUMA peptide binds strongly with p53 DBD, and the crystal structure of p53-PUMA peptide complex revealed it contains four molecules of p53 DBD and one PUMA peptide per asymmetric unit in space group P. PUMA peptide bound to the N-terminal residues of p53 DBD. A cell proliferation assay demonstrated PUMA peptide inhibited the growth of a lung cancer cell line. These results contribute to understanding of the mechanism responsible for p53-mediated apoptosis.
PUMA（p53 上调的凋亡调节剂）定位于线粒体，是 p53 介导的细胞凋亡的直接靶点。p53 通过依赖转录和不依赖转录的机制引发线粒体凋亡。p53 通过转录诱导 PUMA 来诱导细胞凋亡，PUMA 编码 Bcl-2 蛋白家族中具有促凋亡 BH3 结构域的成员。然而，人源性 PUMA 的不依赖转录的机制仍未得到充分阐明。例如，目前尚不清楚 PUMA 是否在体外与 p53 的 DNA 结合域（DBD：残基 92-293）直接相互作用。在这里，通过 X 射线晶体学阐明了 p53 DBD 与 PUMA 肽之间复合物的结构。等温滴定量热法显示，PUMA 肽与 p53 DBD 强烈结合，p53-PUMA 肽复合物的晶体结构显示，在空间群 P 中，每个不对称单位包含四个 p53 DBD 分子和一个 PUMA 肽。PUMA 肽结合在 p53 DBD 的 N 端残基上。细胞增殖测定表明，PUMA 肽抑制了肺癌细胞系的生长。这些结果有助于理解 p53 介导的细胞凋亡的机制。
