Structural basis for the assembly and energy transfer between the cyanobacterial PSI core and the double-layered IsiA proteins.

ABSTRACT: Iron-limitation is a common stress factor in natural environments. To survive under iron-starved conditions, cyanobacteria overexpress iron stress-induced protein A (IsiA), which is crucial for light-harvesting and photoprotection. Multiple IsiA proteins form a single- or double-layered architecture encircling the photosystem I (PSI) core, forming various PSI-IsiA supercomplexes. The assembly and energy transfer mechanisms of double-layered PSI-IsiA supercomplexes remain unelucidated. Here, we present high-resolution structures of two PSI-IsiA supercomplexes isolated from the cyanobacterium Thermosynechococcus elongatus BP-1 cultured under iron-starved conditions. The PSI₃-IsiA₄₃ complex contains a trimeric PSI core surrounded by 43 IsiA subunits assembled into a clos

SUBMITTER: Si L 

PROVIDER: S-EPMC12808642 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature