Alpha-momorcharin: A Ribosome-Inactivating Protein from Momordica charantia, Possessing DNA Cleavage Properties

作者：Wang, Shuzhen; Zheng, Yinzhen; Yan, Junjie; Zhu, Zhixuan; Wu, Zhihua; Ding, Yi^*

来源：Protein and Peptide Letters, 2013, 20(11): 1257-1263.

• Active residue
• activity-related residues
• alpha-momorcharin
• DNase-like activity
• polynucleotide: adenosine glycosidase activity
• ribosome-inactivating proteins

Ribosome-inactivating proteins (RIPs) function to inhibit protein synthesis through the removal of specific adenine residues from eukaryotic ribosomal RNA and rending the 60S subunit unable to bind elongation factor 2. They have received much attention in biological and biomedical research due to their unique activities toward tumor cells, as well as the important roles in plant defense. Alpha-momorcharin (alpha-MC), a member of the type I family of RIPs, is rich in the seeds of Momordica charantia L. Previous studies demonstrated that alpha-MC is an effective antifungal and antibacterial protein. In this study, a detailed analysis of the DNase-like activity of alpha-MC was conducted. Results showed that the DNase-like activity toward plasmid DNA was time-dependent, temperature-related, and pH-stable. Moreover, a requirement for divalent metal ions in the catalytic domain of alpha-MC was confirmed. Additionally, Tyr(93) was found to be a critical residue for the DNase-like activity, while Tyr(134), Glu(183), Arg(186), and Trp(215) were activity-related residues. This study on the chemico-physical properties and mechanism of action of alpha-MC will improve its utilization in scientific research, as well as its potential industrial uses. These results may also assist in the characterization and elucidation of the DNase-like enzymatic properties of other RIPs.

• 出版日期2013-11
• 单位武汉大学; 杂交水稻国家重点实验室