Past Research

RecA protein assures fidelity of DNA repair and genome stability in Deinococcus radiodurans.

RecA protein assures fidelity of DNA repair and genome stability in Deinococcus radiodurans.
Deinococcus radiodurans is one of the most radiation-resistant organisms known. It can repair hundreds of radiation-induced double-strand DNA breaks without loss of viability. Genome reassembly in heavily irradiated D. radiodurans is considered to be an error-free process since no genome rearrangements were detected after post-irradiation repair. Here, we describe for the first time conditions that frequently cause erroneous chromosomal assemblies.

Protein damage and death by radiation in Escherichia coli and Deinococcus radiodurans.

Protein damage and death by radiation in Escherichia coli and Deinococcus radiodurans.
Deinococcus radiodurans is among a small number of bacterial species that are extremely resistant to ionizing radiation, UV light, toxic chemicals, and desiccation. We measured proteome oxidation (i.e., protein carbonylation, PC) in D. radiodurans as well as in standard and evolved resistant strains of Escherichia coli exposed to ionizing radiation or UVC light and found a consistent correlation with cell killing. The unique quantitative relationship between incurred PC and cell death holds over the entire range of killing for all tested bacteria and for both lethal agents, meaning that both bacterial species are equally sensitive to PC.

Unstructured hydrophilic sequences in prokaryotic proteomes correlate with dehydration tolerance and host association.

Unstructured hydrophilic sequences in prokaryotic proteomes correlate with dehydration tolerance and host association.
Here, we explore possible hallmarks of prokaryotic desiccation tolerance in their proteomes. The content of unstructured, low complexity (LC) regions was analyzed in a total of 460 bacterial and archaeal proteomes. It appears that species endowed with proteomes abundant in unstructured hydrophilic LC regions are desiccation-tolerant or sporulating bacteria, halophilic archaea and bacteria, or host-associated species.

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Unstructured hydrophilic sequences in prokaryotic proteomes correlate with dehydration tolerance and host association.

 

 

J Mol Biol. 2010 Oct 8;402(5):775-82. Epub 2010 Aug 13.

 

Source

Institut National de la Santé et de la Recherche Médicale U1001, Université Paris Descartes, Faculté de Médecine, 156 rue de Vaugirard, 75730 Paris Cedex 15, France. anita.krisko@inserm.fr

Abstract

Water loss or desiccation is among the most life-threatening stresses. It leads to DNA double-strand breakage, protein aggregation, cell shrinkage, and low water activity precluding all biological functions. Yet, in all kingdoms of life, rare organisms are resistant to desiccation through prevention or reversibility of such damage. Here, we explore possible hallmarks of prokaryotic desiccation tolerance in their proteomes. The content of unstructured, low complexity (LC) regions was analyzed in a total of 460 bacterial and archaeal proteomes. It appears that species endowed with proteomes abundant in unstructured hydrophilic LC regions are desiccation-tolerant or sporulating bacteria, halophilic archaea and bacteria, or host-associated species. In the desiccation- and radiation-resistant bacterium Deinococcus radiodurans, most proteins that contain large hydrophilic LC regions have unassigned function, but those with known function are mostly involved in diverse cellular recovery processes. Such LC regions are typically absent in orthologous proteins in desiccation-sensitive species. D. radiodurans encodes also special LC proteins, akin to those associated with desiccation resistance of plant seeds and some plants and animals. Therefore, we postulate that large unstructured hydrophilic LC regions and proteins provide for cellular resistance to dehydration and we discuss mechanisms of their protective activity.

Copyright © 2010 Elsevier Ltd. All rights reserved.

PMID:
20709076
[PubMed - indexed for MEDLINE]

 

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Miroslav Radman - Molecular Biology and Genetics Scientist