Basic proteins were isolated from purified pea chloroplast nucleoids by acid extraction. Using RP-HPLC, the component composition of the basic proteins was studied. SDS-PAGE of major HPLC-fractions showed that the basic nucleoid proteins are heterogeneous with mol. masses of components from 17 to 30 kDa. One polypeptide with mol. mass of 28 kDa (P28) was obtained by RP-HPLC. The sequencing of three tryptic peptides of P28 (T6, T17, and T19) showed that they are homologous to the ribosomal protein L19 of Saccharomyces cerevisiae. The possible functional role of ribosomal proteins in chloroplast nucleoids is discussed.
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http://dx.doi.org/10.1080/15216549900201843 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany.
In most bacteria, cell division depends on the tubulin-homolog FtsZ that polymerizes in a GTP-dependent manner to form the cytokinetic Z-ring at the future division site. Subsequently, the Z-ring recruits, directly or indirectly, all other proteins of the divisome complex that executes cytokinesis. A critical step in this process is the precise positioning of the Z-ring at the future division site.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Biophysics & Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Most bacteria lack membrane-enclosed organelles and rely on macromolecular scaffolds at different subcellular locations to recruit proteins for specific functions. Here, we demonstrate that the optogenetic CRY2-CIB1 system from Arabidopsis thaliana can be used to rapidly direct proteins to different subcellular locations with varying efficiencies in live Escherichia coli cells, including the nucleoid, the cell pole, the membrane, and the midcell division plane. Such light-induced re-localization can be used to rapidly inhibit cytokinesis in actively dividing E.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstr 3, 06466 Seeland, Germany.
In eukaryotes, accurate chromosome segregation during cell division relies on the centromeric histone H3 variant, CENH3. Our previous work identified KINETOCHORE NULL2 (αKNL2) as a plant CENH3 assembly factor, which contains a centromere-targeting motif, CENPC-k, analogous to the CENPC motif found in CENP-C. We also demonstrated that αKNL2 can bind DNA in vitro in a sequence-independent manner, without the involvement of its CENPC-k motif.
View Article and Find Full Text PDFmBio
December 2024
Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
Conjugative plasmids are widespread among prokaryotes, highlighting their evolutionary success. Conjugation systems on most natural plasmids are repressed by default. The negative regulation of F-plasmid conjugation is partially mediated by the chromosomal nucleoid-structuring protein (H-NS).
View Article and Find Full Text PDFJ Biol Chem
December 2024
Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China. Electronic address:
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