Resonance Raman spectra of blue copper proteins: Variable temperature spectra of Thermus thermophilus HB27 laccase
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1.
California Institute of Technology
Abstract
The resonance Raman (rR) spectra of the oxidized type 1 copper active site (Cu_(T1)) in Thermus thermophilus HB27 laccase (Tth-lac) has been determined in the 20 to 80 °C temperature range using 633-nm excitation. The positions and relative intensities of rR peaks are virtually independent of temperature, indicating that Cu_(T1) ligation is robust over the investigated range. The intensity-weighted average of Tth-lac Cu-S_(Cys) vibrations (<ν(Cu-S_(Cys))>) = 423 cm⁻¹) is higher than those of most cupredoxins but is comparable to those of other multicopper oxidases (MCOs). <ν(Cu-S_(Cys))> values for Tth-lac and several CuT1 centers in cupredoxins and MCOs do not correlate well with Cu-S_(Cys) bond lengths but do exhibit systematic trends with redox thermodynamic properties.
Prologue
F. Ann Walker was a great scholar and dear friend. While at Columbia in the early 1960s, I (HBG) followed her graduate work at Brown on the effects of axial ligands on vanadyl ion EPR spectra. Dick Carlin, her thesis adviser, invited me to serve as external member of her thesis committee. I joined, made my way to Providence, met her just before the exam, and greatly admired (enjoyed!) her thoughtful responses to questions from physical chemists about metal-oxo electronic structures. Our friendship grew stronger over the years, enhanced by lively discussions of heme protein chemistry in San Francisco, Pasadena, Tucson, and at Gordon Research Conferences. Ann was a superstar in biological inorganic chemistry. She will be sorely missed but not forgotten.
Copyright and License
© 2023 Elsevier.
Acknowledgement
Research reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under award number R01DK019038. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Additional support for this research was provided by the Arnold and Mabel Beckman Foundation.
Contributions
Janice Kang: Investigation, Resources, Methodology, Writing – original draft, Writing – review & editing. Jieun Shin: Investigation, Resources, Methodology, Visualization, Writing – original draft, Writing – review & editing. Harry B. Gray: Funding acquisition, Project administration, Supervision, Writing – review & editing. Jay R. Winkler: Conceptualization, Funding acquisition, Project administration, Supervision, Writing – review & editing.
Data Availability
Data will be made available on request.
Conflict of Interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Harry B. Gray reports financial support was provided by National Institutes of Health. Jay R. Winkler reports financial support was provided by National Institutes of Health.
Additional details
- PMCID
- PMC10529995
- National Institutes of Health
- R01DK019038
- Arnold and Mabel Beckman Foundation