bioRxiv ScienceSearch

Biology subjects

Pang, C.

Publications and source records attributed to Pang, C..

3 recordsLinked to original sources

Accurate Name Entity Recognition for Biomedical Literatures: A Combined High-quality Manual Annotation and Deep-learning Natural Language Processing Study

A combined high-quality manual annotation and deep-learning natural language processing study is reported to make accurate name entity recognition (NER) for biomedical literatures. A home-made version of entity annotation guidelines on biomedical literatures was constructed. Our manual annotations have an overall over 92% consistency for all the four entity types -- gene, variant, disease and species --with the same publicly available annotated corpora from other experts previously. A total of 400 full biomedical articles from PubMed are annotated based on our home-made entity annotation guidelines. Both a BERT-based large model and a DistilBERT-based simplified model were constructed, trained and optimized for offline and online inference, respectively. The F1-scores of NER of gene, variant, disease and species for the BERT-based model are 97.28%, 93.52%, 92.54% and 95.76%, respectively, while those for the DistilBERT-based model are 95.14%, 86.26%, 91.37% and 89.92%, respectively. The F1 scores of the DistilBERT-based NER model retains 97.8%, 92.2%, 98.7% and 93.9% of those of BERT-based NER for gene, variant, disease and species, respectively. Moreover, the performance for both our BERT-based NER model and DistilBERT-based NER model outperforms that of the state-of-art model--BioBERT, indicating the significance to train an NER model on biomedical-domain literatures jointly with high-quality annotated datasets.

bioinformatics

AlphaFold Protein Structure Database for Sequence-Independent Molecular Replacement

Crystallographic phasing recovers the phase information that is lost during a diffraction experiment. Molecular replacement is a dominant phasing method for the crystal structures in the protein data bank. In one form it uses a protein sequence to search a structure database for finding suitable templates for phasing. However, such sequence information is not always available such as when proteins are crystallized with unknown binding partner proteins or when the crystal is that of a contaminant. The recent development of AlphaFold has resulted in the availability of predicted protein structures for all proteins from twenty species. In this work, we tested whether AlphaFold-predicted E. coli protein structures were accurate enough for sequence-independent phasing of diffraction data from two crystallization contaminants for which we had not identified the protein. Using each of more than 4000 predicted structures as a search model, robust molecular replacement solutions were obtained which allowed the identification and structure determination of both structures, YncE and YadF. Our results advocate a general utility of AlphaFold-predicted structure database with respect to crystallographic phasing.

biochemistry

Structural Basis for SARS-CoV-2 Envelope Protein in Recognition of Human Cell Junction Protein PALS1

The COVID-19 pandemic caused by the SARS-CoV-2 virus has created a global health and economic emergency. SARS-CoV-2 viruses hijack human proteins to promote their spread and virulence including the interactions involving the viral envelope (E) protein and human proteins. To understand the structural basis for SARS-CoV-2 viral-host recognition, we used cryo-electron microscopy to determine a structure for the human cell junction protein PALS1 and SARS-CoV-2 E protein complex. The structure shows that the E protein C-terminal DLLV motif recognizes a pocket formed exclusively by hydrophobic residues from the PDZ and SH3 domains in PALS1. Our structural analysis provides an explanation for the observation that the viral E protein recruits PALS1 from lung epithelial cell junctions resulting in vascular leakage, lung damage, viral spread, and virulence. In addition, our structure provides novel targets for peptide- and small-molecule inhibitors that could block the PALS1-E interactions to reduce the E-mediated damage to vascular structures.

biochemistry