Implementation of simultaneous ultraviolet/visible and x-ray absorption spectroscopy with microfluidics.

Area of Science:

• Biophysical chemistry
• Spectroscopic techniques
• Metalloenzyme active site characterization

Background:

• X-ray spectroscopies and UV/Vis spectroscopy are crucial for studying metalloenzyme active sites.
• Current methods often struggle to capture transient, highly reactive intermediates.
• In situ measurements are vital for understanding enzymes under physiological conditions.

Purpose of the Study:

• To develop and implement a novel system for simultaneous in situ UV/Vis and high-energy resolution fluorescence detected X-ray absorption spectroscopy.
• To enable the study of reactive catalytic intermediates at millisecond timescales.
• To overcome limitations of traditional methods like freeze-quenching.

Main Methods:

• Integration of a fiber optic UV/Vis spectrometer and parabolic mirror setup within a dual array valence emission spectrometer.
• Simultaneous data collection at the Photon-In Photon-Out X-ray Spectroscopy beamline.
• Utilizing advanced microfluidic mixing techniques for sample handling.

Main Results:

• Successful simultaneous collection of UV/Vis and X-ray absorption spectra.
• Demonstration of the system's capability with ferricyanide and a dilute iron protein.
• Validation of millisecond timescale measurements of catalytic intermediates.

Conclusions:

• The developed system provides a powerful new tool for in situ metalloenzyme research.
• Enables unprecedented temporal resolution for studying reactive intermediates.
• Facilitates a deeper understanding of catalytic mechanisms under near-physiological conditions.