Resonance Raman spectroscopy of pyranopterin molybdenum enzymes

Resonance Raman spectroscopy (rR) is a powerful spectroscopic probe that is widely used for studying the geometric and electronic structure of metalloproteins. In this focused review, we detail how resonance Raman spectroscopy has contributed to a greater understanding of electronic structure, geometric structure, and the reaction mechanisms of pyranopterin molybdenum enzymes. The review focuses on the enzymes sulfite oxidase (SO), dimethyl sulfoxide reductase (DMSOR), xanthine oxidase (XO), and carbon monoxide dehydrogenase. Specifically, we highlight how Mo-Ooxo, Mo-Ssulfido, Mo-Sdithiolene, and dithiolene CC vibrational modes, isotope and heavy atom perturbations, resonance enhancement, and associated Raman studies of small molecule analogs have provided detailed insight into the nature of these metalloenzyme active sites. Synopsis Resonance Raman spectroscopy has contributed to a greater understanding of pyranopterin molybdenum enzymes. This review primarily focuses on sulfite oxidase, dimethyl sulfoxide reductase, xanthine oxidase, and carbon monoxide dehydrogenase, and details how resonance Raman spectroscopy has provided keen insight into their electronic structures, geometric structures, and mechanisms. [Display omitted] •Resonance Raman spectroscopy is a powerful probe of molybdoenzyme geometric and electronic structure•Raman spectroscopy has contributed to a greater understanding of pyranpterin molybdenum enzyme mechanism.•Resonance Raman studies have primarily focused on the canonical pyranopterin molybdenum enzymes.• Important information is derived from comparing Raman studies of enzyme and model systems.