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The kinetics of the hydrogen/deuterium exchange of epidermal growth factor receptor ligands.

Iloro I, Narváez D, Guillén N, Camacho CM, Guillén L, Cora E, Pastrana-Ríos B - Biophys. J. (2008)

Bottom Line: All ligands were found to have similar contributions of 3(10)-helix and random coil with varying contributions of beta-sheets and beta-turns.The time constants for AR 0.47 min(-1) (Tyr), 0.04 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (buried 3(10)-helix, beta-turns, and beta-sheets); for HB-EGF 0.89 min(-1) (Tyr), 0.14 min(-1) (Arg and 3(10)-helix), and 1.00 x 10(-3) min(-1) (buried 3(10)-helix, beta-sheets, and beta-turns); and for epiregulin 0.16 min(-1) (Tyr), 0.03 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (3(10)-helix and beta-sheets).These results provide essential information toward understanding secondary structure, H/D exchange kinetics, and solvation of these epidermal growth factor receptor ligands in their unbound state.

View Article: PubMed Central - PubMed

Affiliation: Center for Protein Structure Function and Dynamics, University of Puerto Rico, Mayagüez Campus, Mayagüez, Puerto Rico.

ABSTRACT
Five highly homologous epidermal growth factor receptor ligands were studied by mass spectral analysis, hydrogen/deuterium (H/D) exchange via attenuated total reflectance Fourier transform-infrared spectroscopy, and two-dimensional correlation analysis. These studies were performed to determine the order of events during the exchange process, the extent of H/D exchange, and associated kinetics of exchange for a comparative analysis of these ligands. Furthermore, the secondary structure composition of amphiregulin (AR) and heparin-binding-epidermal growth factor (HB-EGF) was determined. All ligands were found to have similar contributions of 3(10)-helix and random coil with varying contributions of beta-sheets and beta-turns. The extent of exchange was 40%, 65%, 55%, 65%, and 98% for EGF, transforming growth factor-alpha (TGF-alpha), AR, HB-EGF, and epiregulin (ER), respectively. The rate constants were determined and classified as fast, intermediate, and slow: for EGF the 0.20 min(-1) (Tyr), 0.09 min(-1) (Arg, beta-turns), and 1.88 x 10(-3) min(-1) (beta-sheets and 3(10)-helix); and for TGF-alpha 0.91 min(-1) (Tyr), 0.27 min(-1) (Arg, beta-turns), and 1.41 x 10(-4) min(-1) (beta-sheets). The time constants for AR 0.47 min(-1) (Tyr), 0.04 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (buried 3(10)-helix, beta-turns, and beta-sheets); for HB-EGF 0.89 min(-1) (Tyr), 0.14 min(-1) (Arg and 3(10)-helix), and 1.00 x 10(-3) min(-1) (buried 3(10)-helix, beta-sheets, and beta-turns); and for epiregulin 0.16 min(-1) (Tyr), 0.03 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (3(10)-helix and beta-sheets). These results provide essential information toward understanding secondary structure, H/D exchange kinetics, and solvation of these epidermal growth factor receptor ligands in their unbound state.

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2DCOS obtained from the baseline-corrected spectra corresponding to EGF and TGF-α (A and C) synchronous and (B and D) asynchronous plots, respectively.
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fig10: 2DCOS obtained from the baseline-corrected spectra corresponding to EGF and TGF-α (A and C) synchronous and (B and D) asynchronous plots, respectively.

Mentions: To enhance the spectral resolution and extract correlation and temporal information of the spectral changes, a two-dimensional correlation analysis was performed on each data set, within the spectral region of 1800–1400 cm−1. The synchronous plots, which reflect in-phase transitions, are shown in Figs. 10, A and C, and 11, A, C, and E; and the asynchronous plots, which reflect out-of-phase transitions, are shown in Figs. 10, B and D, and 11, B, D, and F, for EGF, TGF-α, AR, HB-EGF, and ER, respectively. The auto peaks are diagonal peaks, which reflect intensity variations, whereas crosspeaks are off-diagonal peaks, reflecting correlations. These assignments are summarized in Table 2. At times, there can be small contributions that are difficult to localize due to band overlapping. To confirm the presence of small overlapped peaks, the spectral data were deconvolved (data not shown).


The kinetics of the hydrogen/deuterium exchange of epidermal growth factor receptor ligands.

Iloro I, Narváez D, Guillén N, Camacho CM, Guillén L, Cora E, Pastrana-Ríos B - Biophys. J. (2008)

2DCOS obtained from the baseline-corrected spectra corresponding to EGF and TGF-α (A and C) synchronous and (B and D) asynchronous plots, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2367206&req=5

fig10: 2DCOS obtained from the baseline-corrected spectra corresponding to EGF and TGF-α (A and C) synchronous and (B and D) asynchronous plots, respectively.
Mentions: To enhance the spectral resolution and extract correlation and temporal information of the spectral changes, a two-dimensional correlation analysis was performed on each data set, within the spectral region of 1800–1400 cm−1. The synchronous plots, which reflect in-phase transitions, are shown in Figs. 10, A and C, and 11, A, C, and E; and the asynchronous plots, which reflect out-of-phase transitions, are shown in Figs. 10, B and D, and 11, B, D, and F, for EGF, TGF-α, AR, HB-EGF, and ER, respectively. The auto peaks are diagonal peaks, which reflect intensity variations, whereas crosspeaks are off-diagonal peaks, reflecting correlations. These assignments are summarized in Table 2. At times, there can be small contributions that are difficult to localize due to band overlapping. To confirm the presence of small overlapped peaks, the spectral data were deconvolved (data not shown).

Bottom Line: All ligands were found to have similar contributions of 3(10)-helix and random coil with varying contributions of beta-sheets and beta-turns.The time constants for AR 0.47 min(-1) (Tyr), 0.04 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (buried 3(10)-helix, beta-turns, and beta-sheets); for HB-EGF 0.89 min(-1) (Tyr), 0.14 min(-1) (Arg and 3(10)-helix), and 1.00 x 10(-3) min(-1) (buried 3(10)-helix, beta-sheets, and beta-turns); and for epiregulin 0.16 min(-1) (Tyr), 0.03 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (3(10)-helix and beta-sheets).These results provide essential information toward understanding secondary structure, H/D exchange kinetics, and solvation of these epidermal growth factor receptor ligands in their unbound state.

View Article: PubMed Central - PubMed

Affiliation: Center for Protein Structure Function and Dynamics, University of Puerto Rico, Mayagüez Campus, Mayagüez, Puerto Rico.

ABSTRACT
Five highly homologous epidermal growth factor receptor ligands were studied by mass spectral analysis, hydrogen/deuterium (H/D) exchange via attenuated total reflectance Fourier transform-infrared spectroscopy, and two-dimensional correlation analysis. These studies were performed to determine the order of events during the exchange process, the extent of H/D exchange, and associated kinetics of exchange for a comparative analysis of these ligands. Furthermore, the secondary structure composition of amphiregulin (AR) and heparin-binding-epidermal growth factor (HB-EGF) was determined. All ligands were found to have similar contributions of 3(10)-helix and random coil with varying contributions of beta-sheets and beta-turns. The extent of exchange was 40%, 65%, 55%, 65%, and 98% for EGF, transforming growth factor-alpha (TGF-alpha), AR, HB-EGF, and epiregulin (ER), respectively. The rate constants were determined and classified as fast, intermediate, and slow: for EGF the 0.20 min(-1) (Tyr), 0.09 min(-1) (Arg, beta-turns), and 1.88 x 10(-3) min(-1) (beta-sheets and 3(10)-helix); and for TGF-alpha 0.91 min(-1) (Tyr), 0.27 min(-1) (Arg, beta-turns), and 1.41 x 10(-4) min(-1) (beta-sheets). The time constants for AR 0.47 min(-1) (Tyr), 0.04 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (buried 3(10)-helix, beta-turns, and beta-sheets); for HB-EGF 0.89 min(-1) (Tyr), 0.14 min(-1) (Arg and 3(10)-helix), and 1.00 x 10(-3) min(-1) (buried 3(10)-helix, beta-sheets, and beta-turns); and for epiregulin 0.16 min(-1) (Tyr), 0.03 min(-1) (Arg), and 1.00 x 10(-4) min(-1) (3(10)-helix and beta-sheets). These results provide essential information toward understanding secondary structure, H/D exchange kinetics, and solvation of these epidermal growth factor receptor ligands in their unbound state.

Show MeSH
Related in: MedlinePlus