Databases, Protein ; Protein Structure, Secondary ; Proteins ; chemistry

Objective:To automatically synthesize Al 18F-fibroblast activation protein inhibitor (FAPI)-74, and explore its value of clinical application. Methods:Al 18F-FAPI-74 was synthesized automatically by the commercial synthesis module CFN-MPS-100, and its yield, radiochemical purity and stability were determined. Sixteen normal Kunming (KM) mice were randomly divided into 4 groups and euthanized at 10, 30, 60 and 90 min after Al 18F-FAPI-74 injection, and the biodistribution was measured. MicroPET/CT dynamic scanning (60 min) was performed in 5 rat pancreatic tumor-bearing BALB/c nude mice to observe the tumor uptake. Al 18F-FAPI-74 PET/CT imaging was performed on 3 volunteers (1 male, 2 females; age: 37, 41, 43 years) to evaluate the clinical application value of Al 18F-FAPI-74. Results:The automated synthesis time of Al 18F-FAPI-74 was about 35 min, with the synthesis yield of (21.34±3.86)% (without attenuation correction, n=5) and the radiochemical purity more than 99%. The radiochemical purity was still more than 96% after placement at 37 ℃ for 6 h. Biodistribution in normal mice and microPET/CT dynamic scanning in tumor-bearing nude mice showed that consistently high uptake in the kidneys and bladder, and the tumor uptake was the highest at 20 min, and the maximum tumor-to-muscle ratio was 3.16±0.01 at 60 min. PET/CT imaging on volunteers showed that there was a small amount of uptake in myocardium, most organs such as the liver and lung had background uptake, and the maximum SUV max of persistent high uptake of tumor was 17.08. Conclusions:Al 18F-FAPI-74 has the advantages of simple synthesis, high yield, stable quality and good imaging performance in mice and volunteers. It is a kind of imaging agent that meets the requirements of clinical diagnosis.

Small proteins specifically refer to proteins consisting of less than 100 amino acids translated from small open reading frames (sORFs), which were usually missed in previous genome annotation. The significance of small proteins has been revealed in current years, along with the discovery of their diverse functions. However, systematic annotation of small proteins is still insufficient. SmProt was specially developed to provide valuable information on small proteins for scientific community. Here we present the update of SmProt, which emphasizes reliability of translated sORFs, genetic variants in translated sORFs, disease-specific sORF translation events or sequences, and remarkably increased data volume. More components such as non-ATG translation initiation, function, and new sources are also included. SmProt incorporated 638,958 unique small proteins curated from 3,165,229 primary records, which were computationally predicted from 419 ribosome profiling (Ribo-seq) datasets or collected from literature and other sources from 370 cell lines or tissues in 8 species (Homo sapiens, Mus musculus, Rattus norvegicus, Drosophila melanogaster, Danio rerio, Saccharomyces cere-visiae, Caenorhabditis elegans, and Escherichia coli). In addition, small protein families identified from human micro-biomes were also collected. All datasets in SmProt are free to access, and available for browse, search, and bulk downloads at http://bigdata.ibp.ac.cn/SmProt/.