A highly controllable protein self-assembly system with morphological versatility induced by reengineered host-guest interactions
NANOSCALE
Authors: Li, Xiumei; Bai, Yushi; Huang, Zupeng; Si, Chengye; Dong, Zeyuan; Luo, Quan; Liu, Junqiu
Abstract
Manipulating proteins to self-assemble into highly ordered nanostructures not only provides insights into the natural protein assembly process but also allows access to advanced biomaterials. Host-guest interactions have been widely used in the construction of artificial protein assemblies in recent years. CB[8] can selectively associate with two tripeptide Phe-Gly-Gly (FGG) tags with an extraordinarily high binding affinity (K-ter = 1.5 X 10(11) M-2). However, the FGG tags utilized before are all fixed to the N-termini via genetic fusion; this spatial limitation greatly confined the availability of the CB[8]/FGG pair in the construction of more sophisticated protein nanostructures. Here we first designed and synthesized a maleimide-functionalized Phe-Gly-Gly tag as a versatile site-specific protein modification tool; this designed tag can site-selectively introduce desired guest moieties onto protein surfaces for host-guest driven protein assembly. When regulating the self-assembly process of proteins and CB[8], the constructed protein nanosystem can exhibit distinctive morphological diversities ranging from nanorings, nanospirals, nanowires to super-wires. This work developed a new strategy for site-specific protein modification of the CB[8] binding tag and provides a possible direction for the construction of 'smart', dynamic self-assembly systems.
Discovery of small extracellular vesicle proteins from human serum for liver cirrhosis and liver cancer
BIOCHIMIE
Authors: Uzzaman, Asad; Zhang, Xuguang; Qiao, Zhi; Zhan, Hao; Sohail, Amir; Wahid, Amir; Shang, Zhi; Guan, Xin; Cao, Cheng-Xi; Xiao, Hua
Abstract
Hepatocellular carcinoma (HCC) is a common neoplastic transformation of the hepatocytes, which has high morbidity and mortality worldwide, particularly in Eastern Asia. HCC is also developed as a consequence of chronic liver cirrhosis, and both diseases are difficult to diagnosis and differentiate. Accurate noninvasive biomarkers for HCC and cirrhosis are urgently needed. In the search for novel candidates, small extracellular vesicles (sEVs) were isolated from the serum of liver cancer patients, liver cirrhosis patients, healthy control subjects, as well as the culture media of hepatocellular carcinoma cells (HepG2) and normal hepatocyte cells (Lo2). Isolated sEVs were confirmed by size distribution analysis, morphological analysis, and surface biomarker tests. Mass spectrometry based label-free quantification revealed 61 and 63 differentially expressed proteins in the serum sEVs of liver cirrhosis patients and liver cancer patients (p < 0.05), respectively. The proteomics data of cell-derived sEVs were combined for the selection of valuable candidates. Promising proteins were further verified by immunoassay, including thrombospondin-1 (THBS1), fibulin-1(FBLN1), and fibrinogen gamma chain (FGG), which could differentiate healthy control from liver cancer or liver cirrhosis. Our findings verified the hypothesis that cancer-related proteomics signatures are present in the sEVs of patient's serum and might be monitored for the evaluation of liver cancer and liver cirrhosis. (C) 2020 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.