title: Light-Activated Reversible Imine Isomerization: Towards a Photochromic Protein Switch.
abstract: Mutants of cellular retinoic acid-binding protein II (CRABPII), engineered to bind all-trans-retinal as an iminium species, demonstrate photochromism upon irradiation with light at different wavelengths. UV light irradiation populates the cis-imine geometry, which has a high pKa , leading to protonation of the imine and subsequent "turn-on" of color. Yellow light irradiation yields the trans-imine isomer, which has a depressed pKa , leading to loss of color because the imine is not protonated. The protein-bound retinylidene chromophore undergoes photoinduced reversible interconversion between the colored and uncolored species, with excellent fatigue resistance.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Tetyana
authors.initials: T
authors.lastname: Berbasova
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Santos
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Meisam
authors.initials: M
authors.lastname: Nosrati
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Chrysoula
authors.initials: C
authors.lastname: Vasileiou
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: James H
authors.initials: JH
authors.lastname: Geiger
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Babak
authors.initials: B
authors.lastname: Borhan
mesh_terms: D002851:Chromatography, High Pressure Liquid; D007097:Imines / Q000737:chemistry*; D007536:Isomerism; D011506:Proteins / Q000737:chemistry*; D012172:Retinaldehyde / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014466:Ultraviolet Rays
chemical_list: D007097:Imines; D011506:Proteins; D012172:Retinaldehyde
keywords: imines; isomerization; photochemistry; protein engineering; retinal