Motivation: The object of this study is to propose a new method to identify small compact units that compose protein three-dimensional structures. These fragments, called 'protein units (PU)', are a new level of description to well understand and analyze the organization of protein structures. The method only works from the contact probability matrix, i.e. the inter Calpha-distances translated into probabilities. It uses the principle of conventional hierarchical clustering, leading to a series of nested partitions of the 3D structure. Every step aims at dividing optimally a unit into 2 or 3 subunits according to a criterion called 'partition index' assessing the structural independence of the subunits newly defined. Moreover, an entropy-derived squared correlation R is used for assessing globally the protein structure dissection. The method is compared to other splitting algorithms and shows relevant performance.
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http://dx.doi.org/10.1093/bioinformatics/bti773 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Nanjing University, School of Chemistry and Chemical Engineering, No. 163 Xianlin Road, 210023, Nanjing, CHINA.
Hydroxylation, an extensive post-translational modification on proline, is critical for the modulation of protein structures, further dominating their functions in life systems. However, current mass spectrometry-based identification, could hardly distinguish hydroxylation from neighboring oxidation due to the same mass shifts, as well as challenges posed by low abundance and exogenous oxidation during sample preparation. To address these, an engineered nanopore was designed, capable of discriminating single hydroxyl group, to achieve the identification of proline hydroxylation on individual native peptides directly in the mixture.
View Article and Find Full Text PDFFEBS Lett
January 2025
Allgemeine Botanik, Karlsruhe Institute of Technology, Joseph Kölreuter Institut für Pflanzenwissenschaften (JKIP), Karlsruhe, Germany.
Phytochromes are biliprotein photoreceptors found in bacteria, fungi, and plants. The soil bacterium Agrobacterium fabrum has two phytochromes, Agp1 and Agp2, which work together to control DNA transfer to plants and bacterial conjugation. Both phytochromes interact as homodimeric proteins.
View Article and Find Full Text PDFEnviron Microbiol
January 2025
Department of Biology, University of Oxford, Oxford, UK.
Rhizobia and legumes form a symbiotic relationship resulting in the formation of root structures known as nodules, where bacteria fix nitrogen. Legumes release flavonoids that are detected by the rhizobial nodulation (Nod) protein NodD, initiating the transcriptional activation of nod genes and subsequent synthesis of Nod Factors (NFs). NFs then induce various legume responses essential for this symbiosis.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Chemistry, Institute of Biochemistry, BOKU University, Vienna, Austria.
Prokaryotic heme biosynthesis in Gram-positive bacteria follows the coproporphyrin-dependent heme biosynthesis pathway. The last step in this pathway is catalyzed by the enzyme coproheme decarboxylase, which oxidatively transforms two propionate groups into vinyl groups yielding heme b. The catalytic reaction cycle of coproheme decarboxylases exhibits four different states: the apo-form, the substrate (coproheme)-bound form, a transient three-propionate intermediate form (monovinyl, monopropionate deuteroheme; MMD), and the product (heme b)-bound form.
View Article and Find Full Text PDFProtein Sci
February 2025
Cell Physiology and Molecular Biophysics Department, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas, USA.
Purifying membrane proteins has been the limiting step for studying their structure and function. The challenges of the process include the low expression levels in heterologous systems and the requirement for their biochemical stabilization in solution. The human voltage-gated proton channel (hH1) is a good example of that: the published protocols to express and purify hH1 produce low protein quantities at high costs, which is an issue for systematically characterizing its structure and function.
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