2i2h

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(New page: 200px<br /><applet load="2i2h" size="350" color="white" frame="true" align="right" spinBox="true" caption="2i2h" /> '''NMR structure of TPC3 in TFE'''<br /> ==Ove...)
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==Overview==
==Overview==
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Streptococcus mutans secretes and utilizes a 21-amino-acid signaling, peptide pheromone to initiate quorum sensing for genetic competence, biofilm formation, stress responses, and bacteriocin production. In this, study, we designed and synthesized a series of truncated peptides and, peptides with amino acid substitutions to investigate their, structure-activity relationships based on the three-dimensional structures, of S. mutans wild-type signaling peptide UA159sp and C-terminally, truncated peptide TPC3 from mutant JH1005 defective in genetic competence., By analyzing these peptides, we demonstrated that the signaling peptide of, S. mutans has at least two functional domains. The C-terminal structural, motif consisting of a sequence of polar hydrophobic charged residues is, crucial for activation of the signal transduction pathway, while the core, alpha-helical structure extending from residue 5 to the end of the peptide, is required for receptor binding. Peptides in which three or more residues, were deleted from the C terminus did not induce genetic competence but, competitively inhibited quorum sensing activated by UA159sp. Disruption of, the amphipathic alpha-helix by replacing the Phe-7, Phe-11, or Phe-15, residue with a hydrophilic residue resulted in a significant reduction in, or complete loss of the activity of the peptide. In contrast to the, C-terminally truncated peptides, these peptides with amino acid, substitutions did not compete with UA159sp to activate quorum sensing, suggesting that disruption of the hydrophobic face of the alpha-helical, structure results in a peptide that is not able to bind to the receptor., This study is the first study to recognize the importance of the signaling, peptide C-terminal residues in streptococcal quorum sensing.
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Streptococcus mutans secretes and utilizes a 21-amino-acid signaling peptide pheromone to initiate quorum sensing for genetic competence, biofilm formation, stress responses, and bacteriocin production. In this study, we designed and synthesized a series of truncated peptides and peptides with amino acid substitutions to investigate their structure-activity relationships based on the three-dimensional structures of S. mutans wild-type signaling peptide UA159sp and C-terminally truncated peptide TPC3 from mutant JH1005 defective in genetic competence. By analyzing these peptides, we demonstrated that the signaling peptide of S. mutans has at least two functional domains. The C-terminal structural motif consisting of a sequence of polar hydrophobic charged residues is crucial for activation of the signal transduction pathway, while the core alpha-helical structure extending from residue 5 to the end of the peptide is required for receptor binding. Peptides in which three or more residues were deleted from the C terminus did not induce genetic competence but competitively inhibited quorum sensing activated by UA159sp. Disruption of the amphipathic alpha-helix by replacing the Phe-7, Phe-11, or Phe-15 residue with a hydrophilic residue resulted in a significant reduction in or complete loss of the activity of the peptide. In contrast to the C-terminally truncated peptides, these peptides with amino acid substitutions did not compete with UA159sp to activate quorum sensing, suggesting that disruption of the hydrophobic face of the alpha-helical structure results in a peptide that is not able to bind to the receptor. This study is the first study to recognize the importance of the signaling peptide C-terminal residues in streptococcal quorum sensing.
==About this Structure==
==About this Structure==
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Structure-activity analysis of quorum-sensing signaling peptides from Streptococcus mutans., Syvitski RT, Tian XL, Sampara K, Salman A, Lee SF, Jakeman DL, Li YH, J Bacteriol. 2007 Feb;189(4):1441-50. Epub 2006 Aug 25. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16936029 16936029]
Structure-activity analysis of quorum-sensing signaling peptides from Streptococcus mutans., Syvitski RT, Tian XL, Sampara K, Salman A, Lee SF, Jakeman DL, Li YH, J Bacteriol. 2007 Feb;189(4):1441-50. Epub 2006 Aug 25. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16936029 16936029]
[[Category: Protein complex]]
[[Category: Protein complex]]
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[[Category: Jakeman, D.L.]]
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[[Category: Jakeman, D L.]]
[[Category: Li, Y.]]
[[Category: Li, Y.]]
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[[Category: Syvitski, R.T.]]
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[[Category: Syvitski, R T.]]
[[Category: NH2]]
[[Category: NH2]]
[[Category: helix]]
[[Category: helix]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jan 29 20:33:34 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:48:21 2008''

Revision as of 15:48, 21 February 2008

Image:2i2h.gif

2i2h

Drag the structure with the mouse to rotate

NMR structure of TPC3 in TFE

Overview

Streptococcus mutans secretes and utilizes a 21-amino-acid signaling peptide pheromone to initiate quorum sensing for genetic competence, biofilm formation, stress responses, and bacteriocin production. In this study, we designed and synthesized a series of truncated peptides and peptides with amino acid substitutions to investigate their structure-activity relationships based on the three-dimensional structures of S. mutans wild-type signaling peptide UA159sp and C-terminally truncated peptide TPC3 from mutant JH1005 defective in genetic competence. By analyzing these peptides, we demonstrated that the signaling peptide of S. mutans has at least two functional domains. The C-terminal structural motif consisting of a sequence of polar hydrophobic charged residues is crucial for activation of the signal transduction pathway, while the core alpha-helical structure extending from residue 5 to the end of the peptide is required for receptor binding. Peptides in which three or more residues were deleted from the C terminus did not induce genetic competence but competitively inhibited quorum sensing activated by UA159sp. Disruption of the amphipathic alpha-helix by replacing the Phe-7, Phe-11, or Phe-15 residue with a hydrophilic residue resulted in a significant reduction in or complete loss of the activity of the peptide. In contrast to the C-terminally truncated peptides, these peptides with amino acid substitutions did not compete with UA159sp to activate quorum sensing, suggesting that disruption of the hydrophobic face of the alpha-helical structure results in a peptide that is not able to bind to the receptor. This study is the first study to recognize the importance of the signaling peptide C-terminal residues in streptococcal quorum sensing.

About this Structure

2I2H is a Protein complex structure of sequences from [1] with as ligand. Full crystallographic information is available from OCA.

Reference

Structure-activity analysis of quorum-sensing signaling peptides from Streptococcus mutans., Syvitski RT, Tian XL, Sampara K, Salman A, Lee SF, Jakeman DL, Li YH, J Bacteriol. 2007 Feb;189(4):1441-50. Epub 2006 Aug 25. PMID:16936029

Page seeded by OCA on Thu Feb 21 17:48:21 2008

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