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A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein

Single-stranded DNA binding proteins (SSBs) are vital in all organisms. SSBs of Escherichia coli (EcoSSB) and Mycobacterium tuberculosis (MtuSSB) are homotetrameric. The N-terminal domains (NTD) of these SSBs (responsible for their tetramerization and DNA binding) are structurally well defined. Howe...

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Autores principales: Rex, Kervin, Bharti, Sanjay Kumar, Sah, Shivjee, Varshney, Umesh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983218/
https://www.ncbi.nlm.nih.gov/pubmed/24722671
http://dx.doi.org/10.1371/journal.pone.0094669
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author Rex, Kervin
Bharti, Sanjay Kumar
Sah, Shivjee
Varshney, Umesh
author_facet Rex, Kervin
Bharti, Sanjay Kumar
Sah, Shivjee
Varshney, Umesh
author_sort Rex, Kervin
collection PubMed
description Single-stranded DNA binding proteins (SSBs) are vital in all organisms. SSBs of Escherichia coli (EcoSSB) and Mycobacterium tuberculosis (MtuSSB) are homotetrameric. The N-terminal domains (NTD) of these SSBs (responsible for their tetramerization and DNA binding) are structurally well defined. However, their C-terminal domains (CTD) possess undefined structures. EcoSSB NTD consists of β1-β1′-β2-β3-α-β4-β45(1)-β45(2)-β5 secondary structure elements. MtuSSB NTD includes an additional β-strand (β6) forming a novel hook-like structure. Recently, we observed that MtuSSB complemented an E. coli Δssb strain. However, a chimeric SSB (mβ4-β5), wherein only the terminal part of NTD (β4-β5 region possessing L(45) loop) of EcoSSB was substituted with that from MtuSSB, failed to function in E. coli in spite of its normal DNA binding and oligomerization properties. Here, we designed new chimeras by transplanting selected regions of MtuSSB into EcoSSB to understand the functional significance of the various secondary structure elements within SSB. All chimeric SSBs formed homotetramers and showed normal DNA binding. The mβ4-β6 construct obtained by substitution of the region downstream of β5 in mβ4-β5 SSB with the corresponding region (β6) of MtuSSB complemented the E. coli strain indicating a functional interaction between the L(45) loop and the β6 strand of MtuSSB.
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spelling pubmed-39832182014-04-15 A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein Rex, Kervin Bharti, Sanjay Kumar Sah, Shivjee Varshney, Umesh PLoS One Research Article Single-stranded DNA binding proteins (SSBs) are vital in all organisms. SSBs of Escherichia coli (EcoSSB) and Mycobacterium tuberculosis (MtuSSB) are homotetrameric. The N-terminal domains (NTD) of these SSBs (responsible for their tetramerization and DNA binding) are structurally well defined. However, their C-terminal domains (CTD) possess undefined structures. EcoSSB NTD consists of β1-β1′-β2-β3-α-β4-β45(1)-β45(2)-β5 secondary structure elements. MtuSSB NTD includes an additional β-strand (β6) forming a novel hook-like structure. Recently, we observed that MtuSSB complemented an E. coli Δssb strain. However, a chimeric SSB (mβ4-β5), wherein only the terminal part of NTD (β4-β5 region possessing L(45) loop) of EcoSSB was substituted with that from MtuSSB, failed to function in E. coli in spite of its normal DNA binding and oligomerization properties. Here, we designed new chimeras by transplanting selected regions of MtuSSB into EcoSSB to understand the functional significance of the various secondary structure elements within SSB. All chimeric SSBs formed homotetramers and showed normal DNA binding. The mβ4-β6 construct obtained by substitution of the region downstream of β5 in mβ4-β5 SSB with the corresponding region (β6) of MtuSSB complemented the E. coli strain indicating a functional interaction between the L(45) loop and the β6 strand of MtuSSB. Public Library of Science 2014-04-10 /pmc/articles/PMC3983218/ /pubmed/24722671 http://dx.doi.org/10.1371/journal.pone.0094669 Text en © 2014 Rex et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Rex, Kervin
Bharti, Sanjay Kumar
Sah, Shivjee
Varshney, Umesh
A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title_full A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title_fullStr A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title_full_unstemmed A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title_short A Genetic Analysis of the Functional Interactions within Mycobacterium tuberculosis Single-Stranded DNA Binding Protein
title_sort genetic analysis of the functional interactions within mycobacterium tuberculosis single-stranded dna binding protein
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983218/
https://www.ncbi.nlm.nih.gov/pubmed/24722671
http://dx.doi.org/10.1371/journal.pone.0094669
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