Recent advances in Machine Learning methods in structural biology opened up new perspectives for protein analysis. Utilizing these methods allows us to go beyond the limitations of empirical research, and take advantage of the vast amount of generated data. We use a complete set of potentially knotted protein models identified in all high-quality predictions from the AlphaFold Database to search for any common trends that describe them. We show that the vast majority of knotted proteins have 3 knot and that the presence of knots is preferred in neither Bacteria, Eukaryota, or Archaea domains. On the contrary, the percentage of knotted proteins in any given proteome is around 0.4%, regardless of the taxonomical group. We also verified that the organism's living conditions do not impact the number of knotted proteins in its proteome, as previously expected. We did not encounter an organism without a single knotted protein. What is more, we found four universally present families of knotted proteins in Bacteria, consisting of SAM synthase, and TrmD, TrmH, and RsmE methyltransferases.
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http://dx.doi.org/10.1016/j.jmb.2024.168715 | DOI Listing |
J Mol Biol
January 2025
Department of Biosciences, University of Milan, Italy; Institute of Molecular and Translational Cardiology, IRCCS, Policlinico San Donato, Milan, Italy. Electronic address:
Light chain (AL) amyloidosis is the most common systemic amyloid disease characterized by abnormal accumulation of amyloid fibrils derived from immunoglobulin light chains (LCs). Both full-length (FL) LCs and their isolated variable (VL) and constant (CL) domains contribute to amyloid deposits in multiple organs, with the VL domain predominantly forming the fibril core. However, the role and interplay of these domains in amyloid aggregation and toxicity are poorly understood.
View Article and Find Full Text PDFNat Commun
January 2025
Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA.
Type IA topoisomerases (TopoIAs) are present in all living organisms. They resolve DNA/RNA catenanes, knots and supercoils by breaking and rejoining single-stranded DNA/RNA segments and allowing the passage of another nucleic acid segment through the break. Topoisomerase III-β (TOP3B), the only RNA topoisomerase in metazoans, promotes R-loop disassembly and translation of mRNAs.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
Knotted proteins have a unique topological feature with an open knot, and the physiological significance of these knots remains elusive. In addition, these proteins challenge our understanding of the protein folding process, and whether they retain their native state during unfolding/refolding cycles like other proteins is debated. Most folding studies on knotted proteins have been performed on 3 and 5 knots, monitoring the tryptophan fluorescence.
View Article and Find Full Text PDFCrit Rev Biotechnol
January 2025
Centre of Excellence in Epigenetics, Department of Life Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, India.
G-quadruplex structures (GQSes) are the intricate molecular knots or marvels that play diverse roles in various cellular processes, such as replication, transcription, and translation, which regulate gene expression. Even though GQSes can be found throughout the genome, they are more prevalent in certain genomic regions like promoters and 5'-UTRs. This review discusses the functionality of GQSes across various regions of the genome and draws attention to the intriguing world of DNA and RNA GQSes.
View Article and Find Full Text PDFBMC Plant Biol
December 2024
The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, 430000, China.
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