1. Amino acid selective cross-saturation method for identification of proximal residue pairs in a protein-protein complex
Shunsuke Igarashi, Masanori Osawa, Koh Takeuchi, Shin-ichiro Ozawa, Ichio Shimada J Am Chem Soc. 2008 Sep 10;130(36):12168-76. doi: 10.1021/ja804062t. Epub 2008 Aug 16.
We describe an NMR-based approach, the amino acid selective cross-saturation (ASCS) method, to identify the pairs of the interface residues of protein-protein complexes. ASCS uses a "cross-saturation (CS)-donor" protein, in which only one amino acid is selectively (1)H-labeled in a (2)H-background, and a "CS-acceptor" protein with uniform (2)H, (15)N labeling. Irradiation of the (1)H-labeled amino acid, which exists only in the donor, decreases the intensity of the (1)H- (15)N HSQC signals of the acceptor residues proximal to the (1)H-labeled CS-source residue(s) through the CS phenomenon. Given the three-dimensional structure of each protein in the complex, but not the complex structure, the combinatorial analysis of multiple ASCS results specify the CS-source residue(s), based on the spatial complementarity between the CS-source residues on the CS donor and the cross-saturated amide protons on the acceptor. NMR investigations of the labeling selectivity and efficiency in an E. coli host, which are critical for ASCS, revealed that Ala, Arg, His, Ile, Leu, Lys, Met, Phe, Pro, Trp, and Tyr are selectively labeled with a high (1)H/(2)H ratio. The observation of the ASCS was then confirmed using the known structure of the yeast ubiquitin (Ub) and yeast ubiquitin hydrolase 1 (YUH1). Conversely, reasonable candidates for the CS-source residues were suggested by the analysis of the ASCS results, with reference to the individual structures of YUH1 and Ub. The pairwise distance information between the CS-source residues and the cross-saturated amide groups obtained by ASCS will be useful for modeling protein-protein complexes.
2. Structures and actions of Mytilus inhibitory peptides
T Hirata, I Kubota, N Iwasawa, I Takabatake, T Ikeda, Y Muneoka Biochem Biophys Res Commun. 1988 May 16;152(3):1376-82. doi: 10.1016/s0006-291x(88)80437-6.
Two congeneric peptides that inhibit contraction of the anterior byssus retractor muscle of Mytilus edulis were isolated from the pedal ganglia of the mussel. Their structures were determined to be H-Gly-Ser-Pro-Met-Phe-Val-NH2 and H-Gly-Ala-Pro-Met-Phe-Val-NH2. These hexapeptides also showed inhibitory action on contractions in several other molluscan muscles, such as the cardiac muscle of Meretrix lusoria and the penis retractor muscle of Achatina fulica.
3. Anti-Proliferation Activity of a Decapeptide from Perinereies aibuhitensis toward Human Lung Cancer H1299 Cells
Shuoqi Jiang, Yinglu Jia, Yunping Tang, Die Zheng, Xingbiao Han, Fangmiao Yu, Yan Chen, Fangfang Huang, Zuisu Yang, Guofang Ding Mar Drugs. 2019 Feb 18;17(2):122. doi: 10.3390/md17020122.
Perinereis aibuhitensis peptide (PAP) is a decapeptide (Ile-Glu-Pro-Gly-Thr-Val-Gly-Met-Met-Phe, IEPGTVGMMF) with anticancer activity that was purified from an enzymatic hydrolysate of Perinereis aibuhitensis. In the present study, the anticancer effect of PAP on H1299 cell proliferation was investigated. Our results showed that PAP promoted apoptosis and inhibited the proliferation of H1299 cells in a time- and dose-dependent manner. When the PAP concentration reached 0.92 mM, more than 95% of treated cells died after 72 h of treatment. Changes in cell morphology were further analyzed using an inverted microscope and AO/EB staining and flow cytometry was adopted for detecting apoptosis and cell cycle phase. The results showed that the early and late apoptosis rates of H1299 cells increased significantly after treatment with PAP and the total apoptosis rate was significantly higher than that of the control group. Moreover, after treatment with PAP, the number of cells in the S phase of cells was significantly reduced and the ability for the cells to proliferate was also reduced. H1299 cells were arrested in the G2/M phase and cell cycle progression was inhibited. Furthermore, the results of western blotting showed that nm23-H1 and vascular endothelial growth factor (VEGF) protein levels decreased in a dose-dependent manner, while the pro-apoptotic protein and anti-apoptotic protein ratios and the level of apoptosis-related caspase protein increased in a dose-dependent manner. In conclusion, our results indicated that PAP, as a natural marine bioactive substance, inhibited proliferation and induced apoptosis of human lung cancer H1299 cells. PAP is likely to be exploited as the functional food or adjuvant that may be used for prevention or treatment of human non-small cell lung cancer in the future.
