Structural Analyses of CrtJ and Its B₁₂-Binding Co-Regulators SAerR and LAerR from the Purple Photosynthetic Bacterium Rhodobacter capsulatus.

ABSTRACT: Among purple photosynthetic bacteria, the transcription factor CrtJ is a major regulator of photosystem gene expression. Depending on growing conditions, CrtJ can function as an aerobic repressor or an anaerobic activator of photosystem genes. Recently, CrtJ's activity was shown to be modulated by two size variants of a B₁₂ binding co-regulator called SAerR and LAerR in Rhodobacter capsulatus. The short form, SAerR, promotes CrtJ repression, while the longer variant, LAerR, converts CrtJ into an activator. In this study, we solved the crystal structure of R. capsulatus SAerR at a 2.25 Å resolution. Hydroxycobalamin bound to SAerR is sandwiched between a 4-helix bundle cap, and a Rossman fold. This structure is similar to a AerR-like domain present in CarH from T

SUBMITTER: Dragnea V 

PROVIDER: S-EPMC9144470 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature