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Title: Isotope-enriched protein standards for computational amide I spectroscopy

Abstract

We present a systematic isotope labeling study of the protein G mutant NuG2b as a step toward the production of reliable, structurally stable, experimental standards for amide I infrared spectroscopic simulations. By introducing isotope enriched amino acids into a minimal growth medium during bacterial expression, we induce uniform labeling of the amide bonds following specific amino acids, avoiding the need for chemical peptide synthesis. We use experimental data to test several common amide I frequency maps and explore the influence of various factors on map performance. Comparison of the predicted absorption frequencies for the four maps tested with empirical assignments to our experimental spectra yields a root-mean-square error of 6-12 cm{sup −1}, with outliers of at least 12 cm{sup −1} in all models. This means that the predictions may be useful for predicting general trends such as changes in hydrogen bonding configuration; however, for finer structural constraints or absolute frequency assignments, the models are unreliable. The results indicate the need for careful testing of existing literature maps and shed light on possible next steps for the development of quantitative spectral maps.

Authors:
 [1]; ;  [2]
  1. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  2. Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States)
Publication Date:
OSTI Identifier:
22415584
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; AMINO ACIDS; COMPARATIVE EVALUATIONS; GTP-ASES; HYDROGEN; INFRARED SPECTRA; ISOTOPES; MUTANTS; SYNTHESIS; VISIBLE RADIATION

Citation Formats

Reppert, Mike, Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois 60637, Roy, Anish R., and Tokmakoff, Andrei. Isotope-enriched protein standards for computational amide I spectroscopy. United States: N. p., 2015. Web. doi:10.1063/1.4915271.
Reppert, Mike, Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois 60637, Roy, Anish R., & Tokmakoff, Andrei. Isotope-enriched protein standards for computational amide I spectroscopy. United States. https://doi.org/10.1063/1.4915271
Reppert, Mike, Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois 60637, Roy, Anish R., and Tokmakoff, Andrei. 2015. "Isotope-enriched protein standards for computational amide I spectroscopy". United States. https://doi.org/10.1063/1.4915271.
@article{osti_22415584,
title = {Isotope-enriched protein standards for computational amide I spectroscopy},
author = {Reppert, Mike and Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois 60637 and Roy, Anish R. and Tokmakoff, Andrei},
abstractNote = {We present a systematic isotope labeling study of the protein G mutant NuG2b as a step toward the production of reliable, structurally stable, experimental standards for amide I infrared spectroscopic simulations. By introducing isotope enriched amino acids into a minimal growth medium during bacterial expression, we induce uniform labeling of the amide bonds following specific amino acids, avoiding the need for chemical peptide synthesis. We use experimental data to test several common amide I frequency maps and explore the influence of various factors on map performance. Comparison of the predicted absorption frequencies for the four maps tested with empirical assignments to our experimental spectra yields a root-mean-square error of 6-12 cm{sup −1}, with outliers of at least 12 cm{sup −1} in all models. This means that the predictions may be useful for predicting general trends such as changes in hydrogen bonding configuration; however, for finer structural constraints or absolute frequency assignments, the models are unreliable. The results indicate the need for careful testing of existing literature maps and shed light on possible next steps for the development of quantitative spectral maps.},
doi = {10.1063/1.4915271},
url = {https://www.osti.gov/biblio/22415584}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 12,
volume = 142,
place = {United States},
year = {Sat Mar 28 00:00:00 EDT 2015},
month = {Sat Mar 28 00:00:00 EDT 2015}
}