Correlating structural assemblies of photosynthetic reaction centers on a gold electrode and the photocurrent - potential response

Abstract

Controlled the formation of monolayer or multilayers of RCs on a gold electrode Correlated electrochemical and photocurrent responses to the RC adsorbed conformations measured using AFM Adsorbed RC conformations affect photocurrent generation Photocurrent-potential response influenced by local redox mediator concentration and pH environment experienced by the adsorbed RCs

Closing the green gap of photosystem I with synthetic fluorophores for enhanced photocurrent generation in photobiocathodes

“…Successful setups have been achieved with PSI, 1,5,7,[11][12][13][14][15] PSII, 9,[16][17][18][19][20][21] and bacterial reaction centers. 4,8,[22][23][24][25] But likewise, thylakoid membranes [26][27][28] and even whole cells [29][30][31][32] have been deployed effectively.…”

Purification and preparation of Rhodobacter sphaeroides reaction centers for photocurrent measurements and atomic force microscopy characterization

“…This step begins the process of creating the “Double Mutant” (DM) reaction centers (RCs) for the purpose of the electrochemical experiments. The DM RC is a derivative of the wild type RC, where all native Cys are replaced with Ala or Ser (C(H156)A, C(H234)S, C(L92)S, C(L108)S, C(L247)S) ( Mahmoudzadeh et al., 2011 ); two Cys are introduced in hydrophilic regions to promote binding to a gold surface via a gold-thiol covalent bond ( Jun et al., 2021 ). Note: This step is based on a previous protocol ( Jun et al., 2014 ).…”

“…Examples of expected outcomes and further details of photocurrent measurements, modelling to the Marcus-Hush-Chidsey theory, statistical analysis, and AFM images can be found in Jun et al. (2019 ) and Jun et al. (2021) .…”

“…The initial values do not impact the fitted results except for very noisy or low photocurrent data, but convergence is more reliable if the parameters are estimated starting from the one component fitting results. The use of a second component is statistically validated using an F-test (details elaborated in Jun et al. (2021) ), which compares the reduced model (one component with three parameters) against the full model (two components with six parameters).…”

“…Atomic force microscopy (AFM) is used to characterize the surface and the formation of RC structural assemblies. For complete details on the use and execution of this profile, please refer to Jun et al. (2021) .…”