Site-Specific Characterization of Cytochrome P450cam Conformations by Infrared Spectroscopy

Edward J. Basom, Michal Maj, Minhaeng Cho, Megan C. Thielges

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Conformational changes are central to protein function but challenging to characterize with both high spatial and temporal precision. The inherently fast time scale and small chromophores of infrared (IR) spectroscopy are well-suited for characterization of potentially rapidly fluctuating environments, and when frequency-resolved probes are incorporated to overcome spectral congestion, enable characterization of specific sites in proteins. We selectively incorporated p-cyanophenylalanine (CNF) as a vibrational probe at five distinct locations in the enzyme cytochrome P450cam and used IR spectroscopy to characterize the environments in substrate and/or ligand complexes reflecting those in the catalytic cycle. Molecular dynamics (MD) simulations were performed to provide a structural basis for spectral interpretation. Together the experimental and simulation data suggest that the CN frequencies are sensitive to both long-range influences, resulting from the particular location of a residue within the enzyme, as well as short-range influences from hydrogen bonding and packing interactions. The IR spectra demonstrate that the environments and effects of substrate and/or ligand binding are different at each position probed and also provide evidence that a single site can experience multiple environments. This study illustrates how IR spectroscopy, when combined with the spectral decongestion and spatial selectivity afforded by CNF incorporation, provides detailed information about protein structural changes that underlie function.

Original languageEnglish
Pages (from-to)6598-6606
Number of pages9
JournalAnalytical Chemistry
Volume88
Issue number12
DOIs
Publication statusPublished - 2016 Jun 21

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Camphor 5-Monooxygenase
Cytochromes
Conformations
Infrared spectroscopy
Ligands
Proteins
Substrates
Enzymes
Chromophores
Molecular dynamics
Hydrogen bonds
Infrared radiation
Computer simulation

ASJC Scopus subject areas

  • Analytical Chemistry

Cite this

Site-Specific Characterization of Cytochrome P450cam Conformations by Infrared Spectroscopy. / Basom, Edward J.; Maj, Michal; Cho, Minhaeng; Thielges, Megan C.

In: Analytical Chemistry, Vol. 88, No. 12, 21.06.2016, p. 6598-6606.

Research output: Contribution to journalArticle

Basom, Edward J. ; Maj, Michal ; Cho, Minhaeng ; Thielges, Megan C. / Site-Specific Characterization of Cytochrome P450cam Conformations by Infrared Spectroscopy. In: Analytical Chemistry. 2016 ; Vol. 88, No. 12. pp. 6598-6606.
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