Chemical denaturation of gas-phase albumin ions studied by photoelectron detachment yield spectroscopy and infrared laser ablation of droplet beams

[Display omitted] •PDY spectra of BSA and CTAB-denatured BSA ions were first measured in the gas phase.•Disappearance of a PDY peak by CTAB attachment shows its tertiary structural change.•CTAB attachment on BSA suppresses a reverse reaction from denatured to native form. Chemical denaturation of protein represents a secondary/tertiary structural change, which has been measured by absorption and CD spectra in the liquid phase. In this study, we used gas-phase photoelectron detachment yield (PDY) spectra for elucidating isolated structures of bovine serum albumin (BSA) ions and their conjugated ions with cetyltrimethylammonium bromide (CTAB), whose conjugation causes a significant chemical denaturation in the protein structure. The obtained PDY spectrum of BSA ions shows a broad peak near 208 nm, which significantly disappears in that of CTAB-denatured BSA. This result indicates the CTAB-denatured BSA has a stable unfolding structure in the isolated water cluster.