Is the A_-1 Pigment in Photosystem I Part of P700? A (P700⁺-P700) FTIR Difference Spectroscopy Study of A_-1 Mutants.

ABSTRACT: The involvement of the second pair of chlorophylls, termed A_-1A and A_-1B, in light-induced electron transfer in photosystem I (PSI) is currently debated. Asparagines at PsaA600 and PsaB582 are involved in coordinating the A_-1B and A_-1A pigments, respectively. Here we have mutated these asparagine residues to methionine in two single mutants and a double mutant in PSI from Synechocystis sp. PCC 6803, which we term NA600M, NB582M, and NA600M/NB582M mutants. (P700⁺-P700) FTIR difference spectra (DS) at 293 K were obtained for the wild-type and the three mutant PSI samples. The wild-type and mutant FTIR DS differ considerably. This difference indicates that the observed changes in the (P700⁺-P700) FTIR DS cannot be due to

SUBMITTER: Kirpich JS 

PROVIDER: S-EPMC11084411 | biostudies-literature | 2024 Apr

REPOSITORIES: biostudies-literature