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Cloning and Sequencing Analysis of the Repressor Gene of Temperate Mycobacteriophage L1
Sau, Subrata,Chattoraj, Partho,Ganguly, Tridib,Lee, Chia Yen,Mandal, Nitai Chandra Korean Society for Biochemistry and Molecular Biol 2004 Journal of biochemistry and molecular biology Vol.37 No.2
The wild-type and temperature-sensitive (ts) repressor genes were cloned from the temperate mycobacteriophage L1 and its mutant L1cIts391, respectively. A sequencing analysis revealed that the $131^{st}$ proline residue of the wild-type repressor was changed to leucine in the ts mutant repressor. The 100% identity that was discovered between the two DNA regions of phages L1 and L5, carrying the same sets of genes including their repressor genes, strengthened the speculation that L1 is a minor variant of phage L5 or vice versa. A comparative analysis of the repressor proteins of different mycobacteriophages suggests that the mycobacteriophage-specific repressor proteins constitute a new family of repressors, which were possibly evolved from a common ancestor. Alignment of the mycobacteriophage-specific repressor proteins showed at least 7 blocks (designated I-VII) that carried 3-8 identical amino acid residues. The amino acid residues of blocks V, VI, and some residues downstream to block VI are crucial for the function of the L1 (or L5) repressor. Blocks I and II possibly form the turn and helix 2 regions of the HTH motif of the repressor. Block IV in the L1 repressor is part of the most charged region encompassing amino acid residues 72-92, which flanks the putative N-terminal basic (residues 1-71) and C-terminal acidic (residues 93-183) domains of L1 repressor.
Ganguly, Tridib,Chattoraj, Partho,Das, Malabika,Chanda, Palas K.,Mandal, Nitai.C.,Lee, Chia Y.,Sau, Subrata Korean Society for Biochemistry and Molecular Biol 2004 Journal of biochemistry and molecular biology Vol.37 No.6
The wild-type repressor CI of temperate mycobacteriophage L1 and the temperature-sensitive (ts) repressor CIts391 of a mutant L1 phage, L1cIts391, have been separately overexpressed in E. coli. Both these repressors were observed to specifically bind with the same cognate operator DNA. The operator-binding activity of CIts391 was shown to differ significantly than that of the CI at 32 to $42^{\circ}C$. While 40-95% operator-binding activity was shown to be retained at 35 to $42^{\circ}C$ in CI, more than 75% operator-binding activity was lost in CIts391 at 35 to $38^{\circ}C$, although the latter showed only 10% less binding compared to that of the former at $32^{\circ}C$. The CIts391 showed almost no binding at $42^{\circ}C$. An in vivo study showed that the CI repressor inhibited the growth of a clear plaque former mutant of the L1 phage more strongly than that of the CIts391 repressor at both 32 and $42^{\circ}C$. The half-life of the CIts391-operator complex was found to be about 8 times less than that of the CI-operator complex at $32^{\circ}C$. Interestingly, the repressor-operator complexes preformed at $0^{\circ}C$ have shown varying degrees of resistance to dissociation at the temperatures which inhibit the formation of these complexes are inhibited. The CI repressor, but not that of CIts391, regains most of the DNA-binding activity on cooling to $32^{\circ}C$ after preincubation at 42 to $52^{\circ}C$. All these data suggest that the 131st proline residue at the C-terminal half of CI, which changed to leucine in the CIts391, plays a crucial role in binding the L1 repressor to the cognate operator DNA, although the helix-turn-helix DNA-binding motif of the L1 repressor is located at its N-terminal end.
Cloning and Sequencing Analysis of the Repressor Gene of Temperate Mycobacteriophage L1
( Subrata Sau ),( Partho Chattoraj ),( Tridib Ganguly ),( Chia Yen Lee ),( Nitai Chandra Mandal ) 생화학분자생물학회 2004 BMB Reports Vol.37 No.2
The wild-type and temperature-sensitive (ts) repressor genes were cloned from the temperate mycobacteriophage L1 and its mutant L1cIts391, respectively. A sequencing analysis revealed that the 131` proline residue of the wild-type repressor was changed to leucine in the ts mutant repressor. The 100% identity that was discovered between the two DNA regions of phages L1 and L5, carrying the same sets of genes including their repressor genes, strengthened the speculation that L1 is a minor variant of phage L5 or vice versa. A comparative analysis of the repressor proteins of different mycobacteriophages suggests that the mycobacteriophage-specific repressor proteins constitute a new family of repressors, which were possibly evolved from a common ancestor. Alignment of the mycobacteriophage-specificrepressor proteins showed at least 7 blocks (designated I-VII) that carried 3-8 identical amino acid residues. The amino acid residues of blocks V, VI, and some residues downstream to block VI are crucial for the function of the L1 or L5) repressor. Blocks I and II possibly form the turn and helix 2 regions of the HTH motif of the repressor. Block IV in the L1 repressor is part of the most charged region encompassing amino acid residues 72-92, which flanks the putative N-terminal basic (residues 1-71) and C-terminal acidic (residues 93-183) domains of L1 repressor.
( Tridib Ganguly ),( Partho Chattoraj ),( Malabika Das ),( Palas K. Chanda ),( Nitai. C. Mandal ),( Chia Y. Lee ),( Subrata Sau ) 생화학분자생물학회 2004 BMB Reports Vol.37 No.6
The wild-type repressor CI of temperate mycobacteriophage Ll and the temperature-sensitive (ts) repressor CIts391 of a mutant Ll phage, LlcIts391, have been separately overexpressed in E. coli. Both these repressors were observed to specifically bind with the same cognate operator DNA. The operator-binding activity of CIts391 was shown to differ significantly than that of the CI at 32 to 42C. While 40-95% operator-binding activity was shown to be retained at 35 to 42C in CI, more than 75% operator-binding activity was lost in CIts391 at 35 to 38℃, although the latter showed only 10% less binding compared to that of the former at 32℃. The CIts391 showed almost no binding at 42℃. An in vivo study showed that the CI repressor inhibited the growth of a clear plaque former mutant of the L1 phage more strongly than that of the CIts391 repressor at both 32 and 42℃. The half-life of the CIts391-operator complex was found to be about 8 times less than that of the CI-operator complex at 32C. Interestingly, the repressor-operator complexes preformed at 0C have shown varying degrees of resistance to dissociation at the temperatures which inhibit the formation of these complexes are inhibited. The CI repressor, but not that of CIts391, regains most of the DNA-binding activity on cooling to 32C after preincubation at 42 to 52C. All these data suggest that the 131 proline residue at the C-terminal half of CI, which changed to leucine in the CIts391, plays a crucial role in binding the L1 repressor to the cognate operator DNA, although the helix-turn-helix DNA-binding motif of the LI repressor is located at its N-terminal end.
The COVID-19 Pandemic and the ‘stranded’ Migrant Population: An Unequal pain
AKM Ahsan Ullah,Diotima Chattoraj,Wan Zawawi Ibrahim 부산외국어대학교 아세안연구원 2022 Suvannabhumi Vol.14 No.2
This article aims to determine the vulnerability of migrant populations to COVID-19. Between March 2020 and November 2021, informal interviews with respondents who were stranded in various parts of the world were conducted through Skype and WhatsApp. COVID-19 endangers millions of individuals who were stranded between their homes and their destinations — and who were compelled to reside in overcrowded accommodation where the ideas of "stay home," "keep safe," and "social distancing" have little significance.
Purification and Characterization of Repressor of Temperate S. aureus Phage Φ11
Das, Malabika,Ganguly, Tridib,Chattoraj, Partho,Chanda, Palas Kumar,Bandhu, Amitava,Lee, Chia Yen,Sau, Subrata Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.5
To gain insight into the structure and function of repressor proteins of bacteriophages of gram-positive bacteria, repressor of temperate Staphylococcus aureus phage ${\phi}11$ was undertaken as a model system here and purified as an N-terminal histidine-tagged variant (His-CI) by affinity chromatography. A ~19 kDa protein copurified with intact His-CI (~ 30 kDa) at low level was resulted most possibly due to partial cleavage at its Ala-Gly site. At ~10 nM and higher concentrations, His-CI forms significant amount of dimers in solution. There are two repressor binding sites in ${\phi}11$ cI-cro intergenic region and binding to two sites occurs possibly by a cooperative manner. Two sites dissected by HincII digestion were designated operators $O_L$ and $O_R$, respectively. Equilibrium binding studies indicate that His-CI binds to $O_R$ with a little more strongly than $O_L$ and binding species is probably dimeric in nature. Interestingly His-CI binding affinity reduces drastically at elevated temperatures ($32-42^{\circ}C$). Both $O_L$ and $O_R$ harbor a nearly identical inverted repeat and studies show that ${\phi}11$ repressor binds to each repeat efficiently. Additional analyses indicate that ${\phi}11$ repressor, like $\lambda$ repressor, harbors an N-terminal domain and a C-terminal domain which are separated by a hinge region. Secondary structure of ${\phi}11$ CI even nearly resembles to that of $\lambda$ phage repressor though they differ at sequence level. The putative N-terminal HTH (helix-turn-helix) motif of ${\phi}11$ repressor belongs to the HTH -XRE-family of proteins and shows significant identity to the HTH motifs of some proteins of evolutionary distant organisms but not to HTH motifs of most S. aureus phage repressors.
Cnu, a Novel oriC-Binding Protein of Escherichia coli
Kim, Myung Suk,Bae, Sung-Hun,Yun, Sang Hoon,Lee, Hee Jung,Ji, Sang Chun,Lee, Ji Hyun,Srivastava, Preeti,Lee, Seol-Hoon,Chae, Huiseok,Lee, Younghoon,Choi, Byong-Seok,Chattoraj, Dhruba K.,Lim, Heon M. American Society for Microbiology 2005 Journal of Bacteriology Vol.187 No.20
<B>ABSTRACT</B><P>We have found, using a newly developed genetic method, a protein (named Cnu, for <I>oriC</I>-binding <I>nu</I>cleoid-associated) that binds to a specific 26-base-pair sequence (named <I>cnb</I>) in the origin of replication of <I>Escherichia coli, oriC</I>. Cnu is composed of 71 amino acids (8.4 kDa) and shows extensive amino acid identity to a group of proteins belonging to the Hha/YmoA family. Cnu was previously discovered as a protein that, like Hha, complexes with H-NS in vitro. Our in vivo and in vitro assays confirm the results and further suggest that the complex formation with H-NS is involved in Cnu/Hha binding to <I>cnb</I>. Unlike the <I>hns</I> mutants, elimination of either the <I>cnu</I> or <I>hha</I> gene did not disturb the growth rate, origin content, and synchrony of DNA replication initiation of the mutants compared to the wild-type cells. However, the <I>cnu hha</I> double mutant was moderately reduced in origin content. The Cnu/Hha complex with H-NS thus could play a role in optimal activity of <I>oriC</I>.</P>