Defining the Epitope Region of a Peptide from the Streptomyces coelicolor Phosphoenolpyruvate:Sugar Phosphotransferase System Able to Bind to the Enzyme I
The bacterial PEP:sugar PTS consists of a cascade of several proteins involved in the uptake and phosphorylation of carbohydrates, and in signal transduction pathways. Its uniqueness in bacteria makes the PTS a target for new antibacterial drugs. These drugs can be obtained from peptides or protein...
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Published in | Biophysical journal Vol. 95; no. 3; pp. 1336 - 1348 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.08.2008
Biophysical Society The Biophysical Society |
Subjects | |
Online Access | Get full text |
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Summary: | The bacterial PEP:sugar PTS consists of a cascade of several proteins involved in the uptake and phosphorylation of carbohydrates, and in signal transduction pathways. Its uniqueness in bacteria makes the PTS a target for new antibacterial drugs. These drugs can be obtained from peptides or protein fragments able to interfere with the first reaction of the protein cascade: the phosphorylation of the HPr by the first enzyme, the so-called enzyme EI. To that end, we designed a peptide, HPr
9–30, spanning residues 9 to 30 of the intact HPr protein, containing the active site histidine (His-15) and the first
α-helix of HPr of
Streptomyces coelicolor, HPr
sc. By using fluorescence and circular dichroism, we first determined qualitatively that HPr
sc and HPr
9–30 did bind to EI
sc, the enzyme EI from
S. coelicolor. Then, we determined quantitatively the binding affinities of HPr
9–30 and HPr
sc for EI
sc by using ITC and STD-NMR. The STD-NMR experiments indicate that the epitope region of HPr
9–30 was formed by residues Leu-14, His-15, Ile-21, and Val-23. The binding reaction between EI
sc and HPr
sc is enthalpy driven and in other species is entropy driven; further, the affinity of HPr
sc for EI
sc was smaller than in other species. However, the affinity of HPr
9–30 for EI
sc was only moderately lower than that of EI
sc for HPr
sc, suggesting that this peptide could be considered a promising hit compound for designing new inhibitors against the PTS. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Editor: Doug Barrick. Abbreviations used: PEP, phosphoenolpyruvate; CD, circular dichroism; EIsc, enzyme I of Streptomyces coelicolor; EIec, enzyme I of E. coli; HPrec, histidine phosphocarrier protein of Escherichia coli; HPrsc, histidine phosphocarrier protein of Streptomyces coelicolor; HPr9–30, peptide comprising residues Gly-9 to Gly-30 of the intact HPrsc; ITC, isothermal titration calorimetry; NMR, nuclear magnetic resonance; PTS, sugar phosphotransferase system; STD, saturation transfer difference; TFE, trifluoroethanol; TSP, sodium trimethylsilyl [2,2,3,3-2H4] propionate; UV, ultraviolet. Address reprint requests to Adrián Velázquez-Campoy, Instituto de Biocomputación y Física de los Sistemas Complejos, Corona de Aragón, 42, 50009 Zaragoza, Spain. Tel.: 34-976-562215; Fax: 34-976-562215; E-mail: adrianvc@unizar.es.; or José L. Neira, Instituto de Biología Molecular y Celular, Edificio Torregaitán, Universidad Miguel Hernández, Avda. del Ferrocaril s/n, 03202, Elche (Alicante), Spain. Tel.: 34-966658459. Fax: 34-966658758. E-mail: jlneira@umh.es. |
ISSN: | 0006-3495 1542-0086 |
DOI: | 10.1529/biophysj.107.126664 |