title: A comparative proteomic approach to better define Deinococcus nucleoid specificities.
abstract: Compared to radiation-sensitive bacteria, the nucleoids of radiation-resistant Deinococcus species show a higher degree of compaction. Such a condensed nucleoid may contribute to the extreme radiation resistance of Deinococcus by limiting dispersion of radiation-induced DNA fragments. Architectural proteins may play a role in this high degree of nucleoid compaction, but comparative genomics revealed only a limited number of Deinococcus homologs of known nucleoid-associated proteins (NAPs) from other species such as Escherichia coli. A comparative proteomic approach was used to identify potentially novel proteins from isolated nucleoids of Deinococcus radiodurans and Deinococcus deserti. Proteins in nucleoid enriched fractions were identified and semi-quantified by shotgun proteomics. Based on normalized spectral counts, the histone-like DNA-binding protein HU appeared to be the most abundant among candidate NAPs from both micro-organisms. By immunofluorescence microscopy, D. radiodurans HU and both DNA gyrase subunits were shown to be distributed throughout the nucleoid structure and absent from the cytoplasm. Taken together, our results suggest that D. radiodurans and D. deserti bacteria contain a very low diversity of NAPs, with HU and DNA gyrase being the main proteins involved in the organization of the Deinococcus nucleoids.
authors.affiliation: Univ. Paris-Sud 11, CNRS UMR 8621, CEA LRC 42V, Institut de Génétique et Microbiologie, Bâtiment 409, Université Paris Sud, F-91405 Orsay Cedex, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Toueille
authors.forename: Boris
authors.initials: B
authors.lastname: Mirabella
authors.forename: Philippe
authors.initials: P
authors.lastname: Guérin
authors.forename: Claire
authors.initials: C
authors.lastname: Bouthier de la Tour
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Boisnard
authors.forename: Hong Ha
authors.initials: HH
authors.lastname: Nguyen
authors.forename: Laurence
authors.initials: L
authors.lastname: Blanchard
authors.forename: Pascale
authors.initials: P
authors.lastname: Servant
authors.forename: Arjan
authors.initials: A
authors.lastname: de Groot
authors.forename: Suzanne
authors.initials: S
authors.lastname: Sommer
authors.forename: Jean
authors.initials: J
authors.lastname: Armengaud
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D027081:DNA Gyrase / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification; D034301:Deinococcus / Q000235:genetics* / Q000528:radiation effects; D015388:Organelles / Q000737:chemistry / Q000378:metabolism*; D040901:Proteomics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C040330:histone-like protein HU, bacteria; D027081:DNA Gyrase