Dynamics of the bacterial SMC complex and SMC-like proteins involved in DNA repair

Graumann, Peter L.; Knust, Tobias

doi:10.1007/s10577-008-9014-x

Cited by 73 publications

(75 citation statements)

References 40 publications

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“…The ATPase Activity of RecN Is Stimulated by Duplex DNASequence analysis of bacterial RecN proteins demonstrates that RecN includes two well known motifs (Walker A and Walker B) involved in ATP binding and hydrolysis as well as significant homology to the SMC family of proteins (20,51). Therefore, we have begun the biochemical characterization of RecN by exploring its ATP hydrolysis activity.…”

Section: Resultsmentioning

confidence: 99%

“…However, no dependence of this activity on ATP binding was observed for cohesin complex (31), whereas ATP is stimulatory to the RecN protein (see above). Most SMC proteins, either eukaryotic or prokaryotic, exist as complexes that include non-SMC subunits (22,51). This can complicate attribution of functional characteristics to the SMC protein itself.…”

Section: Discussionmentioning

confidence: 99%

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RecN Is a Cohesin-like Protein That Stimulates Intermolecular DNA Interactions in Vitro

Reyes

Patidar

Uranga

et al. 2010

Journal of Biological Chemistry

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The bacterial RecN protein is involved in the recombinational repair of DNA double-stranded breaks, and recN mutants are sensitive to DNA-damaging agents. Little is known about the biochemical function of RecN. Protein sequence analysis suggests that RecN is related to the SMC (structural maintenance of chromosomes) family of proteins, predicting globular N-and C-terminal domains connected by an extensive coil-coiled domain. The N-and C-domains contain the nucleotide-binding sequences Walker A and Walker B, respectively. We have purified the RecN protein from Deinococcus radiodurans and characterized its DNA-dependent and DNA-independent ATPase activity. The cellular genome maintenance processes of DNA replication, recombination, and repair are highly interconnected, sharing multiple pathways and common enzymes. A physical understanding of the function of key enzymes involved in genome maintenance processes is critical for elucidating the basic DNA metabolic strategies of cells. The primary function of homologous DNA recombination in mitotic cells as well as bacterial cells is the nonmutagenic repair of replication forks that have stalled or collapsed at noncoding lesions or breaks (1-3). When a replication fork encounters a break in the phosphodiester backbone of one template strand, a double-stranded break (DSB) 2 results (4). Recombinational DSB repair pathways promote strand invasion to regenerate a fork structure. In Escherichia coli, these pathways include the helicase and nuclease functions of the RecBCD complex, and the RecA protein. RecN, among various other proteins, is required for DSB repair in bacteria. Existing DSB repair models do not encompass RecN, because no clear function has been ascribed to the protein as yet.The recN gene of E. coli (also known as radB (5)) was identified by two groups over 20 years ago. Lloyd et al. (6) isolated a mutation (rec-259) that caused increased sensitivity to UV light in a recBC sbcB background. Independently, Sargentini and Smith (7) isolated the radB101 mutation, which caused sensitivity to ␥-irradiation and mitomycin C. Expression of the recN gene is regulated by the LexA repressor (8, 9), and the RecN protein is one of the most abundantly produced proteins induced as part of the SOS response to DNA damage (10). Once produced in response to damage, RecN protein has a very short half-life (ϳ10 min), because it apparently is rapidly proteolyzed by the ClpXP protease system (11).The recN gene product was originally placed in the RecF-dependent gap repair pathway, but substantial evidence suggests that RecN is also involved in the RecBCD DSB repair pathway. Unlike other members of the RecF pathway, recN mutants are quite sensitive to ionizing radiation or mitomycin C, and the repair of multiple, site-specific DSBs does not occur in the absence of RecN (8,12,13). The recN gene is also required for the suppression of chromosomal rearrangements and deletions (12) during the repair of a single DSB. Given this wealth of genetic data, the RecN protein is clearly involve...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

RecN Is a Cohesin-like Protein That Stimulates Intermolecular DNA Interactions in Vitro

Reyes

Patidar

Uranga

et al. 2010

Journal of Biological Chemistry

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“…Most if not all species of bacteria and archaea have a single condensin-like complex composed of three subunits: SMC, ScpA, and ScpB (hereafter referred to as the SMC-ScpAB complex) (Graumann and Knust 2009). On the other hand, some species belonging to a subclass of g-proteobacteria, which includes Escherichia coli, have a distinct complex composed of MukB, MukE, and MukF (referred to as the MukBEF complex) instead of SMC-ScpAB (Hiraga 2000).…”

Section: Bacteria/archaeamentioning

confidence: 99%

Condensins: universal organizers of chromosomes with diverse functions

2012

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Condensins are multisubunit protein complexes that play a fundamental role in the structural and functional organization of chromosomes in the three domains of life. Most eukaryotic species have two different types of condensin complexes, known as condensins I and II, that fulfill nonoverlapping functions and are subjected to differential regulation during mitosis and meiosis. Recent studies revealed that the two complexes contribute to a wide variety of interphase chromosome functions, such as gene regulation, recombination, and repair. Also emerging are their cell type- and tissue-specific functions and relevance to human disease. Biochemical and structural analyses of eukaryotic and bacterial condensins steadily uncover the mechanisms of action of this class of highly sophisticated molecular machines. Future studies on condensins will not only enhance our understanding of chromosome architecture and dynamics, but also help address a previously underappreciated yet profound set of questions in chromosome biology.

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“…The protein identified in spot 10 represents a structural maintenance of chromosomes (SMC) protein. SMC proteins belong to a ubiquitous protein family present in almost all prokaryotic and eukaryotic organisms and have functions in chromosome condensation, segregation, cohesion, and DNA recombination and repair (Graumann and Knust, 2009). In E. coli, SMC proteins were shown to induce negative supercoiling of DNA in vivo, indicating their involvement in organization and compaction of nucleoids (Graumann and Knust, 2009).…”

Section: Proteomic Identification Of Chloroplast Nucleoid-associated mentioning

confidence: 99%

“…SMC proteins belong to a ubiquitous protein family present in almost all prokaryotic and eukaryotic organisms and have functions in chromosome condensation, segregation, cohesion, and DNA recombination and repair (Graumann and Knust, 2009). In E. coli, SMC proteins were shown to induce negative supercoiling of DNA in vivo, indicating their involvement in organization and compaction of nucleoids (Graumann and Knust, 2009). An SMC (At-SMC1) as well as an armadillo/b-catenin protein were previously identified in the proteome of chloroplasts from Arabidopsis (Kleffmann et al, 2004;Zybailov et al, 2008).…”

Section: Proteomic Identification Of Chloroplast Nucleoid-associated mentioning

confidence: 99%

The Core of Chloroplast Nucleoids Contains Architectural SWIB Domain Proteins

et al. 2012

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A highly enriched fraction of the transcriptionally active chromosome from chloroplasts of spinach (Spinacia oleracea) was analyzed by two-dimensional gel electrophoresis and mass spectrometry to identify proteins involved in structuring of the nucleoid core. Among such plastid nucleoid-associated candidate proteins a 12-kD SWIB (SWI/SNF complex B) domaincontaining protein was identified. It belongs to a subgroup of low molecular mass SWIB domain proteins, which in Arabidopsis thaliana has six members (SWIB-1 to SWIB-6) with predictions for localization in the two DNA-containing organelles. Green/red fluorescent protein fusions of four of them were shown to be targeted to chloroplasts, where they colocalize with each other as well as with the plastid envelope DNA binding protein in structures corresponding to plastid nucleoids. For SWIB-6 and SWIB-4, a second localization in mitochondria and nucleus, respectively, could be observed. SWIB-4 has a histone H1 motif next to the SWIB domain and was shown to bind to DNA. Moreover, the recombinant SWIB-4 protein was shown to induce compaction and condensation of nucleoids and to functionally complement a mutant of Escherichia coli lacking the histone-like nucleoid structuring protein H-NS.

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Dynamics of the bacterial SMC complex and SMC-like proteins involved in DNA repair

Cited by 73 publications

References 40 publications

RecN Is a Cohesin-like Protein That Stimulates Intermolecular DNA Interactions in Vitro

RecN Is a Cohesin-like Protein That Stimulates Intermolecular DNA Interactions in Vitro

Condensins: universal organizers of chromosomes with diverse functions

The Core of Chloroplast Nucleoids Contains Architectural SWIB Domain Proteins

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