Mechanism of Lutein to <i>meso</i>-Zeaxanthin Isomerization by RPE65 Catalysis.

ABSTRACT: The macular pigments lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) protect the human retina from light and oxidative stress. While L and Z are abundant in the human diet, MZ is nearly absent. We previously demonstrated MZ is derived from L in chicken embryos precisely timed with expression of RPE65. Herein, we show that RPE65 from mouse, an animal that does not concentrate MZ in the eye, catalyzes L to MZ isomerization similarly as found for RPE65 from chicken and human, when expressed in cultured cells. Co-expression with xanthophyll-binding proteins had no impact on MZ yield. L and MZ both fit deep into the tunnel accessing the non-heme iron center, with strain evident for the 3'R,6'R ε ring of L. Interestingly, a negatively charged Glu148, found along substrate tunn

SUBMITTER: Ballinger A 

PROVIDER: S-EPMC12710743 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature