• Title, Summary, Keyword: RecA Protein

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Analysis of Double Stranded DNA-dependent Activities of Deinococcus radiodurans RecA Protein

  • Kim, Jong-Il
    • Journal of Microbiology
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    • v.44 no.5
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    • pp.508-514
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    • 2006
  • In this study, the double-stranded DNA-dependent activities of Deinococcus radiodurans RecA protein (Dr RecA) were characterized. The interactions of the Dr RecA protein with double-stranded DNA were determined, especially dsDNA-dependent ATP hydrolysis by the Dr RecA protein and the DNA strand exchange reaction, in which multiple branch points exist on a single RecA protein-DNA complex. A nucleotide cofactor (ATP or dATP ) was required for the Dr RecA protein binding to duplex DNA. In the presence of dATP, the nucleation step in the binding process occurred more rapidly than in the presence of ATP. Salts inhibited the binding of the Dr RecA protein to double-stranded DNA. Double-stranded DNA-dependent ATPase activities showed a different sensitivity to anion species. Glutamate had only a minimal effect on the double-stranded DNA-dependent ATPase activities, up to a concentration of 0.7 M. In the competition experiment for Dr RecA protein binding, the Dr RecA protein manifested a higher affinity to double-stranded DNA than was observed for single-stranded DNA.

Characterization of Single Stranded DNA-Dependent ATPase Activities of Deinococcus radiodurans RecA Protein (Deinococcus radiodurans RecA 단백질의 외가닥 DNA-의존성 ATPase 활성 분석)

  • Kim, Jong-Il
    • Korean Journal of Microbiology
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    • v.43 no.4
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    • pp.250-255
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    • 2007
  • The RecA protein of Deinococcus radiodurans is essential for the extreme radiation resistance of this organism. The central steps involved in recombinational DNA repair require DNA-dependent ATP hydrolysis by recA protein. Key feature of RecA protein-mediated activities is the interactions with ssDNA and dsDNA. The ssDNA is the site where RecA protein filament formation nucleates and where initiation of DNA strand exchange takes place. The effect of sequence heterogeneity of ssDNA was examined in this experiment. The rate of homopolymeric synthetic ssDNA-dependent ATP hydrolysis was constant or nearly so over a broader range of pHs. For poly(dT)-dependent ATP or dATP hydrolysis, rates were generally faster, with a broader optimum between pH 7.0 and 8.0. Activities of RecA protein were affected by the ionic environment. The ATPase activity was shown to have different sensitivity to anionic species. The presence of glutamate seemed to slimulate the hydrolytic activity. Dr RecA protein was shown to require $Mg^{2+}$ ion greater than 2 mM for binding to etheno ssDNA and the binding stoichiometry of 3 nucleotide for RecA protein monomer.

The RecA-like protein of Schizosoccharomvces pombe: its cellular level is induced by DNA-damaging agents (DNA 상해요인에 의한 Schizosaccharomyces pombe RecA 유사 단백질의 유도생성)

  • 이정섭;박상대
    • The Korean Journal of Zoology
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    • v.37 no.2
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    • pp.232-239
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    • 1994
  • RecA protein plans a central role in homologous recombination and DNA repair in Escherichia cofi (E. colD. The function 8nd structure of this protein are universal in prokarvotes and also conserved in eukaryotes such as yeast. The RecA-like protein with 74 lInDa in size has already been identified and purified from a fission yeast Schizosaccharomyces pombe (5. pommel (Lee, 19911. From this study it was revealed that the RecA-like protein of 5. pombe was highly inducible to various DNA damaging agents and inhibitors of nucleotide pool svnthesizins enzymes. The cellular level of the 5. pombe RecA-like protein wi,u markedly increased, upto 5- to 10-fold, by treatment with various DNA-damains agents including ultraviolet (UV) light, methyl methanesulfonate WS),4-nitroquinoline-1-oxide (4-NQO), and mitomycin-C (MMC), similar to E. cofi RecA protein. Interestingly, the protein level was also increased by inhibitors of nucleotide pool forming enzlwnes such as methotrexate (MTX) and hvdroxvurea (HU). The most effective doses for the inducibility of 4-NQO, MMS, W, MMC, MTX, and HU were 0.2 Ug/ml, 30 mM, 200 J/ma, 0.4 $\mus/ml,$ 1 Ug/ml, and 100 mM, respectively. The range of effective duration time for the inducibilitv of RecA-like protein was from 270 to 450 mins. These results suggest that the 5. pombe RecA-like protein also platys an imortant role in cellular responses to DNA damage as in E. coli system.

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Effect of Cobaltous Chloride on the Repair of UV-induced DNA Damage (UV에 의해 손상된 DNA 회복에 미치는 cobaltous chloride의 효과)

  • Kim, Kug-Chan;Kim, Yung-Jin;Lee, Kang-Suk
    • Journal of Radiation Protection and Research
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    • v.20 no.2
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    • pp.71-78
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    • 1995
  • To develop methods to reduce radiation risk and apply such knowledge to improvement of radiation protection, the effects of cobaltous chloride known as bioantimutagen on the function of E. coli RecA protein involved in the repair of DNA damage were examined. The results demonstrated two distinct effects of cobaltous chloride on the RecA protein function necessary for the strand exchange reaction. Cobaltous chloride enhanced the ability of RecA protein to displace SSB protein from single-stranded DNA and the duplex DNA-dependent ATPase activity. RecA protein was preferentially bound with UV-irradiated supercoiled DNA as compared with nonirradiated DNA The binding of RecA protein to UV-irradiated supercoiled DNA was enhanced in a dose-dependent manner. It is likely that studies on the factors affecting repair efficiency and the DNA repair proteins may provide information on the repair of ionizing radiation-induced DNA damage and the mechanism for DNA radioprotection.

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A small recA analog in streptococcus pneumoniae that is not induced during competence for genetic transformation (폐염균에서 작은 RecA 유사체의 검출 및 형질전환 때의 비유도성 확인)

  • ;Morrison, Donald A.
    • Korean Journal of Microbiology
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    • v.27 no.2
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    • pp.162-167
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    • 1989
  • Western blot analysis of lysates of Streptococcus pneumoniae revealed a single polypeptide species that cross-reacted with E. coli RecA antiserum. The apparent molecular weight of this putative RecA protein analog (RecAsp) was 24, 000 smaller than any other known RecA analogue. The RecAsp protein was present at the same level in competent and non-competent cells.

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DNA-Independent ATPase Activity of Deinococcus radiodurans RecA Protein Is Activated by High Salt (고농도 염에 의한 Deinococcus radiodurans RecA 단백질의 DNA 비의존성 ATPase 역가의 활성화)

  • Kim, Jong-Il
    • Korean Journal of Microbiology
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    • v.46 no.4
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    • pp.313-318
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    • 2010
  • Deinococcus radiodurans RecA protein, when bound to DNA, exhibits a DNA-dependent ATPase. In the absence of DNA, the rate of RecA protein-promoted ATP hydrolysis drops 1,000-fold under the physiological concentrations of salt. This DNA-independent activity can be stimulated to levels approximating those observed with DNA by adding high concentrations (approximately 1.6 M) of a wide variety of salts. This effect was characterized by varying salt concentration and comparing the effects of different ion types. The higher concentrations of salt stimulated the ATP hydrolysis by RecA protein in the absence of DNA. At 1.6 M chloride, the observed stimulation showed the following cation trend $K^+{\geq}Na^+$ > $NH_4^+$ and the following anion sequence was observed: $glutamate^- \; > \; C1^- \;> \; acetate^-\; > \;PO_4^-$ at 1.6 M $K^+$. The catalytic properties of the salt-stimulated ATP hydrolysis reaction was optimal between pH 7.0 and 8.0, which was similar to the double stran nded DNA-dependent ATPase activities of Deinococcus radiodurans RecA protein. In the absence of DNA the active species for ATP hydrolysis by RecA protein was shown to be an aggregate of three RecA protein molecules.

Physiological Relevance of Salt Environment for in vitro recA System

  • Kim, Jong-Il
    • Journal of Microbiology
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    • v.37 no.2
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    • pp.59-65
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    • 1999
  • RecA protein can promote strand assimilation, homologous pairing, and strand exchange. All these reactions require DNA-dependent ATP hydrolysis by recA protein, and the activities of recA protein are affected by the ionic environment. In this experiment, DNA-dependent ATPase activity showed different sensitivity to anionic species. ATP hydrolysis and strand exchange were relatively sensitive to salt in the reactions with NaCl, strongly inhibited at 100 mM NaCl. However, the inhibition by sodium acetate or sodium glutamate was not observed at 50∼100 mM concentration. Addition of sodium glutamate to the standard reaction condition increased the apparent efficiency of ATP hydrolysis during strand exchange. The condition including 50∼100 mM sodium-glutamate might be similar to the physiological condition.

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Joint Interactions of SSB with RecA Protein on Single-Stranded DNA

  • Kim, Jong-Il
    • Journal of Microbiology and Biotechnology
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    • v.9 no.5
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    • pp.562-567
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    • 1999
  • Single-stranded DNA binding protein (SSB) is well-characterized as having a helix-destabilizing activity. The helix-destabilizing capability of SSB has been re-examined in this study. The results of restriction endonuclease protection assays and titration experiments suggest that the stimulatory effect of SSB on strand exchange acts by melting out the secondary structure which is inaccessible to RecA protein binding; however, SSB is excluded from regions of secondary structure present in native single-stranded DNA. Complexes of SSB and RecA protein are required for eliminating the secondary structure barriers under optimal conditions for strand exchange.

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Ribonucleotide Reductase Activity of Schizosaccbarornyces pombe Is Inhibited by Escherichia coli RecA Antibody (Schizosaccbarornyces pombe에서 Escherichia coli RecA 항체에 의한 Ribonucleotide Reductase 효소활성 저해)

  • Lee, Jung-Sup;Chun, Min-Suck;Kim, Ok-Bong;Park, Jong-Kun;Kim, Si-Wouk;Park, Yeal;Yang, Young-Ki;Hong, Seung-Hwan;Park, Sang-Dai
    • The Korean Journal of Zoology
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    • v.38 no.4
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    • pp.565-569
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    • 1995
  • We have previoosly demonstrated that the RecA-like protein of Schizosaccharomyces pombe (S. pombe) is immunologically related to Escherichia coil (E. coil) RecA protein and that the cellular level of the protein is significantly increased by inhibitors of nucleotide pool-forming enzymes such as hydroxyurea (HU) and methotrexate (MTX) (lee and Park, 1994; lee et al., 1994). In this study, we report that the ribonudeotide redudase activity of S. pombe is inhibited by E. coil RecA antibody, as determined by thin layer chromatography using [5-$^3$H]CDP as a substrate. The relative activity of ribonucleotide reductase was dramatically inhibited by 100 mM of flu (26.4% reduction) in in vitro assay, compared to that of non-treated control. The ribonucleotide reductase activity was also inhibited by immunoprecipitation with E. coil RecA antibody (43.3% reduction). These results indicate that the strudure of S. pombe ribonucleotide reductase is in part similar to that of E. coil RecA protein.

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Molecular Cloning and Characterization of a recA-like Gene Induced by DNA Damage from a Fluorescent Pseudomonas sp.

  • Ok Bong Kim;Na Young Kim;Jae Hoon Jeong;Si Wouk Kim;Hye Gwang Jeong;Seong Myeong Yoon;Jong Kun Park;Jung Sup Lee
    • Animal cells and systems
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    • v.3 no.2
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    • pp.229-236
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    • 1999
  • The recA gene plays a central role in genetic recombination and SOS DNA repair in Escherichia coli (E. coli). We have previously identified a 42 kDa RecA-like protein inducible by a variety of DNA damages from a fluorescent Pseudomonas strain sp. and characterized its inducible kinetics. In the present study, we cloned and characterized the gene encoding the RecA-like protein by immunological screening of Pseudomonas genomic expression library using polyclonal E. coli anti-RecA antibodies as a probe. From 10$^{5}$ plaques screened, five putative clones were finally isolated. Southern blot analysis indicated that four clones had the same DNA inserts and the recA-like gene was located within the 3.2 kb EcoRI fragment of Pseudomonas chromosomal DNA. In addition, the cloned recA-like gene was transcribed into an RNA transcript approximately 1.1 kb in size, as judged by Northern blot analysis. The cellular level of RNA transcript of the cloned recA-like gene was increased to an average of 5.15- fold upon treatment with DNA damaging agents such as ultraviolet (UV)- light, nalidixic acid (NA), methyl methanesulfonate (MMS), and mitomycin-C (MMC). These results suggest that the cloned gene is inducible by DNA damage similarly to the recA gene in E. coli. However, the cloned gene did not restore the DNA damage sensitivity of the E. coli recA-mutant.

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