1.Three-dimensional domain swapping as a mechanism to lock the active conformation in a super-active octamer of SARS-CoV main protease.
Shengnan ZHANG ; Nan ZHONG ; Fei XUE ; Xue KANG ; Xiaobai REN ; Jiaxuan CHEN ; Changwen JIN ; Zhiyong LOU ; Bin XIA
Protein & Cell 2010;1(4):371-383
Proteolytic processing of viral polyproteins is indispensible for the lifecycle of coronaviruses. The main protease (M(pro)) of SARS-CoV is an attractive target for anti-SARS drug development as it is essential for the polyprotein processing. M(pro) is initially produced as part of viral polyproteins and it is matured by autocleavage. Here, we report that, with the addition of an N-terminal extension peptide, M(pro) can form a domain-swapped dimer. After complete removal of the extension peptide from the dimer, the mature M(pro) self-assembles into a novel super-active octamer (AO-M(pro)). The crystal structure of AO-M(pro) adopts a novel fold with four domain-swapped dimers packing into four active units with nearly identical conformation to that of the previously reported M(pro) active dimer, and 3D domain swapping serves as a mechanism to lock the active conformation due to entanglement of polypeptide chains. Compared with the previously well characterized form of M(pro), in equilibrium between inactive monomer and active dimer, the stable AO-M(pro) exhibits much higher proteolytic activity at low concentration. As all eight active sites are bound with inhibitors, the polyvalent nature of the interaction between AO-M(pro) and its polyprotein substrates with multiple cleavage sites, would make AO-M(pro) functionally much more superior than the M(pro) active dimer for polyprotein processing. Thus, during the initial period of SARS-CoV infection, this novel active form AOM(pro) should play a major role in cleaving polyproteins as the protein level is extremely low. The discovery of AOM(pro) provides new insights about the functional mechanism of M(pro) and its maturation process.
Coronavirus
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metabolism
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Cysteine Endopeptidases
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Endopeptidases
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metabolism
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Humans
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Peptides
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chemistry
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metabolism
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Polyproteins
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chemistry
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metabolism
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Protein Binding
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SARS Virus
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chemistry
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metabolism
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Viral Proteins
2.Nanoplateletsomes restrain metastatic tumor formation through decoy and active targeting in a preclinical mouse model.
Longlong ZHANG ; Yuefei ZHU ; Xunbin WEI ; Xing CHEN ; Yang LI ; Ying ZHU ; Jiaxuan XIA ; Yiheng HUANG ; Yongzhuo HUANG ; Jianxin WANG ; Zhiqing PANG
Acta Pharmaceutica Sinica B 2022;12(8):3427-3447
Platelets buoy up cancer metastasis via arresting cancer cells, enhancing their adhesion, and facilitating their extravasation through the vasculature. When deprived of intracellular and granular contents, platelet decoys could prevent metastatic tumor formation. Inspired by these, we developed nanoplatesomes by fusing platelet membranes with lipid membranes (P-Lipo) to restrain metastatic tumor formation more efficiently. It was shown nanoplateletsomes bound with circulating tumor cells (CTC) efficiently, interfered with CTC arrest by vessel endothelial cells, CTC extravasation through endothelial layers, and epithelial-mesenchymal transition of tumor cells as nanodecoys. More importantly, in the mouse breast tumor metastasis model, nanoplateletsomes could decrease CTC survival in the blood and counteract metastatic tumor growth efficiently by inhibiting the inflammation and suppressing CTC escape. Therefore, nanoplatelesomes might usher in a new avenue to suppress lung metastasis.
3.Single-dose AAV-based vaccine induces a high level of neutralizing antibodies against SARS-CoV-2 in rhesus macaques.
Dali TONG ; Mei ZHANG ; Yunru YANG ; Han XIA ; Haiyang TONG ; Huajun ZHANG ; Weihong ZENG ; Muziying LIU ; Yan WU ; Huan MA ; Xue HU ; Weiyong LIU ; Yuan CAI ; Yanfeng YAO ; Yichuan YAO ; Kunpeng LIU ; Shifang SHAN ; Yajuan LI ; Ge GAO ; Weiwei GUO ; Yun PENG ; Shaohong CHEN ; Juhong RAO ; Jiaxuan ZHAO ; Juan MIN ; Qingjun ZHU ; Yanmin ZHENG ; Lianxin LIU ; Chao SHAN ; Kai ZHONG ; Zilong QIU ; Tengchuan JIN ; Sandra CHIU ; Zhiming YUAN ; Tian XUE
Protein & Cell 2023;14(1):69-73