Biomaterial Database

Illuminating the "Twilight Zone": Advances in Difficult Protein Modeling. 2023

Damian Bartuzi, and Agnieszka A Kaczor, and Dariusz Matosiuk

Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Laboratory, Medical University of Lublin, Lublin, Poland. damian.bartuzi@umlub.pl.

Homology modeling was long considered a method of choice in tertiary protein structure prediction. However, it used to provide models of acceptable quality only when templates with appreciable sequence identity with a target could be found. The threshold value was long assumed to be around 20-30%. Below this level, obtained sequence identity was getting dangerously close to values that can be obtained by chance, after aligning any random, unrelated sequences. In these cases, other approaches, including ab initio folding simulations or fragment assembly, were usually employed. The most recent editions of the CASP and CAMEO community-wide modeling methods assessment have brought some surprising outcomes, proving that much more clues can be inferred from protein sequence analyses than previously thought. In this chapter, we focus on recent advances in the field of difficult protein modeling, pushing the threshold deep into the "twilight zone", with particular attention devoted to improvements in applications of machine learning and model evaluation.

UI	MeSH Term	Description	Entries
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D000069550	Machine Learning	A type of ARTIFICIAL INTELLIGENCE that enable COMPUTERS to independently initiate and execute LEARNING when exposed to new data.	Transfer Learning,Learning, Machine,Learning, Transfer
D017434	Protein Structure, Tertiary	The level of protein structure in which combinations of secondary protein structures (ALPHA HELICES; BETA SHEETS; loop regions, and AMINO ACID MOTIFS) pack together to form folded shapes. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure.	Tertiary Protein Structure,Protein Structures, Tertiary,Tertiary Protein Structures
D017510	Protein Folding	Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.	Protein Folding, Globular,Folding, Globular Protein,Folding, Protein,Foldings, Globular Protein,Foldings, Protein,Globular Protein Folding,Globular Protein Foldings,Protein Foldings,Protein Foldings, Globular
D019295	Computational Biology	A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.	Bioinformatics,Molecular Biology, Computational,Bio-Informatics,Biology, Computational,Computational Molecular Biology,Bio Informatics,Bio-Informatic,Bioinformatic,Biologies, Computational Molecular,Biology, Computational Molecular,Computational Molecular Biologies,Molecular Biologies, Computational
D020539	Sequence Analysis, Protein	A process that includes the determination of AMINO ACID SEQUENCE of a protein (or peptide, oligopeptide or peptide fragment) and the information analysis of the sequence.	Amino Acid Sequence Analysis,Peptide Sequence Analysis,Protein Sequence Analysis,Sequence Determination, Protein,Amino Acid Sequence Analyses,Amino Acid Sequence Determination,Amino Acid Sequence Determinations,Amino Acid Sequencing,Peptide Sequence Determination,Protein Sequencing,Sequence Analyses, Amino Acid,Sequence Analysis, Amino Acid,Sequence Analysis, Peptide,Sequence Determination, Amino Acid,Sequence Determinations, Amino Acid,Acid Sequencing, Amino,Analyses, Peptide Sequence,Analyses, Protein Sequence,Analysis, Peptide Sequence,Analysis, Protein Sequence,Peptide Sequence Analyses,Peptide Sequence Determinations,Protein Sequence Analyses,Protein Sequence Determination,Protein Sequence Determinations,Sequence Analyses, Peptide,Sequence Analyses, Protein,Sequence Determination, Peptide,Sequence Determinations, Peptide,Sequence Determinations, Protein,Sequencing, Amino Acid,Sequencing, Protein
D030562	Databases, Protein	Databases containing information about PROTEINS such as AMINO ACID SEQUENCE; PROTEIN CONFORMATION; and other properties.	Amino Acid Sequence Databases,Databases, Amino Acid Sequence,Protein Databases,Protein Sequence Databases,SWISS-PROT,Protein Structure Databases,SwissProt,Database, Protein,Database, Protein Sequence,Database, Protein Structure,Databases, Protein Sequence,Databases, Protein Structure,Protein Database,Protein Sequence Database,Protein Structure Database,SWISS PROT,Sequence Database, Protein,Sequence Databases, Protein,Structure Database, Protein,Structure Databases, Protein