Cargando…

Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function

ssDNA, which is involved in numerous aspects of chromosome biology, is managed by a suite of proteins with tailored activities. The majority of these proteins bind ssDNA indiscriminately, exhibiting little apparent sequence preference. However, there are several notable exceptions, including the Sac...

Descripción completa

Detalles Bibliográficos
Autores principales: Glustrom, Leslie W., Lyon, Kenneth R., Paschini, Margherita, Reyes, Cynthia M., Parsonnet, Nicholas V., Toro, Tasha B., Lundblad, Victoria, Wuttke, Deborah S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6187146/
https://www.ncbi.nlm.nih.gov/pubmed/30249661
http://dx.doi.org/10.1073/pnas.1722147115
_version_ 1783362972349890560
author Glustrom, Leslie W.
Lyon, Kenneth R.
Paschini, Margherita
Reyes, Cynthia M.
Parsonnet, Nicholas V.
Toro, Tasha B.
Lundblad, Victoria
Wuttke, Deborah S.
author_facet Glustrom, Leslie W.
Lyon, Kenneth R.
Paschini, Margherita
Reyes, Cynthia M.
Parsonnet, Nicholas V.
Toro, Tasha B.
Lundblad, Victoria
Wuttke, Deborah S.
author_sort Glustrom, Leslie W.
collection PubMed
description ssDNA, which is involved in numerous aspects of chromosome biology, is managed by a suite of proteins with tailored activities. The majority of these proteins bind ssDNA indiscriminately, exhibiting little apparent sequence preference. However, there are several notable exceptions, including the Saccharomyces cerevisiae Cdc13 protein, which is vital for yeast telomere maintenance. Cdc13 is one of the tightest known binders of ssDNA and is specific for G-rich telomeric sequences. To investigate how these two different biochemical features, affinity and specificity, contribute to function, we created an unbiased panel of alanine mutations across the Cdc13 DNA-binding interface, including several aromatic amino acids that play critical roles in binding activity. A subset of mutant proteins exhibited significant loss in affinity in vitro that, as expected, conferred a profound loss of viability in vivo. Unexpectedly, a second category of mutant proteins displayed an increase in specificity, manifested as an inability to accommodate changes in ssDNA sequence. Yeast strains with specificity-enhanced mutations displayed a gradient of viability in vivo that paralleled the loss in sequence tolerance in vitro, arguing that binding specificity can be fine-tuned to ensure optimal function. We propose that DNA binding by Cdc13 employs a highly cooperative interface whereby sequence diversity is accommodated through plastic binding modes. This suggests that sequence specificity is not a binary choice but rather is a continuum. Even in proteins that are thought to be specific nucleic acid binders, sequence tolerance through the utilization of multiple binding modes may be a broader phenomenon than previously appreciated.
format Online
Article
Text
id pubmed-6187146
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher National Academy of Sciences
record_format MEDLINE/PubMed
spelling pubmed-61871462018-10-15 Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function Glustrom, Leslie W. Lyon, Kenneth R. Paschini, Margherita Reyes, Cynthia M. Parsonnet, Nicholas V. Toro, Tasha B. Lundblad, Victoria Wuttke, Deborah S. Proc Natl Acad Sci U S A Biological Sciences ssDNA, which is involved in numerous aspects of chromosome biology, is managed by a suite of proteins with tailored activities. The majority of these proteins bind ssDNA indiscriminately, exhibiting little apparent sequence preference. However, there are several notable exceptions, including the Saccharomyces cerevisiae Cdc13 protein, which is vital for yeast telomere maintenance. Cdc13 is one of the tightest known binders of ssDNA and is specific for G-rich telomeric sequences. To investigate how these two different biochemical features, affinity and specificity, contribute to function, we created an unbiased panel of alanine mutations across the Cdc13 DNA-binding interface, including several aromatic amino acids that play critical roles in binding activity. A subset of mutant proteins exhibited significant loss in affinity in vitro that, as expected, conferred a profound loss of viability in vivo. Unexpectedly, a second category of mutant proteins displayed an increase in specificity, manifested as an inability to accommodate changes in ssDNA sequence. Yeast strains with specificity-enhanced mutations displayed a gradient of viability in vivo that paralleled the loss in sequence tolerance in vitro, arguing that binding specificity can be fine-tuned to ensure optimal function. We propose that DNA binding by Cdc13 employs a highly cooperative interface whereby sequence diversity is accommodated through plastic binding modes. This suggests that sequence specificity is not a binary choice but rather is a continuum. Even in proteins that are thought to be specific nucleic acid binders, sequence tolerance through the utilization of multiple binding modes may be a broader phenomenon than previously appreciated. National Academy of Sciences 2018-10-09 2018-09-24 /pmc/articles/PMC6187146/ /pubmed/30249661 http://dx.doi.org/10.1073/pnas.1722147115 Text en Copyright © 2018 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/ This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Biological Sciences
Glustrom, Leslie W.
Lyon, Kenneth R.
Paschini, Margherita
Reyes, Cynthia M.
Parsonnet, Nicholas V.
Toro, Tasha B.
Lundblad, Victoria
Wuttke, Deborah S.
Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title_full Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title_fullStr Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title_full_unstemmed Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title_short Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
title_sort single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function
topic Biological Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6187146/
https://www.ncbi.nlm.nih.gov/pubmed/30249661
http://dx.doi.org/10.1073/pnas.1722147115
work_keys_str_mv AT glustromlesliew singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT lyonkennethr singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT paschinimargherita singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT reyescynthiam singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT parsonnetnicholasv singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT torotashab singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT lundbladvictoria singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction
AT wuttkedeborahs singlestrandedtelomerebindingproteinemploysadualrheostatforbindingaffinityandspecificitythatdrivesfunction