15N photo-CIDNP MAS NMR analysis of reaction centers of Chloracidobacterium thermophilum

Citation:

Zill JC, He Z, Tank M, Ferlez BH, Canniffe DP, Lahav Y, Bellstedt P, Alia A, Schapiro I, Golbeck JH, et al. 15N photo-CIDNP MAS NMR analysis of reaction centers of Chloracidobacterium thermophilum. Photosynthesis Research [Internet]. 2018;137 (2) :295-305.

Abstract:

Photochemically induced dynamic nuclear polarization (photo-CIDNP) has been observed in the homodimeric, type-1 photochemical reaction centers (RCs) of the acidobacterium, Chloracidobacterium (Cab.) thermophilum, by 15N magic-angle spinning (MAS) solid-state NMR under continuous white-light illumination. Three light-induced emissive (negative) signals are detected. In the RCs of Cab. thermophilum, three types of (bacterio)chlorophylls have previously been identified: bacteriochlorophyll a (BChl a), chlorophyll a (Chl a), and Zn-bacteriochlorophyll a′ (Zn-BChl a′) (Tsukatani et al. in J Biol Chem 287:5720–5732, 2012). Based upon experimental and quantum chemical 15N NMR data, we assign the observed signals to a Chl a cofactor. We exclude Zn-BChl because of its measured spectroscopic properties. We conclude that Chl a is the primary electron acceptor, which implies that the primary donor is most likely Zn-BChl a′. Chl a and 81-OH Chl a have been shown to be the primary electron acceptors in green sulfur bacteria and heliobacteria, respectively, and thus a Chl a molecule serves this role in all known homodimeric type-1 RCs.

Publisher's Version

DOI: 10.1007/s11120-018-0504-1
Last updated on 11/14/2018