Reaction centers of Rhodobacter sphaeroides R-26 with selective replacement of bacteriopheophytin by pheophytin a: I. Characterisation of steady-state absorbance and circular dichroism, and of the P+QA− state

Author(s):
Franken, E.M.; Shkuropatov, A.Y.; Francke, C.; Neerken, S.; Gast, P.; Shuvalov, V.A.; Hoff, A.J.; Aartsma, T.J. (0000-0001-5496-0240)
Published
1997
Publication type
Article / Letter to editor

Abstract

Bacteriopheophytin (BPheo) a of reaction centers (RCs) of Rhodobacter sphaeroides R-26 has been exchanged with pheophytin (Pheo) a. By varying the incubation temperature of the pigment exchange procedure two types of RCs were obtained, with either only the BPheo in the B-chain (BPheo(B)) or both BPheo(B) and BPheo(A) replaced by Pheo a. For the two RC types absorption and CD spectra at 6 K as well as P(+)Q(A)(-) difference spectra at 10 K are compared with those of native RCs. The most pronounced differences are observed in the Q(Y) and Q(X) regions of the (B)Pheos. The P(+)Q(A)(-) decay halftime is for RCs with Pheo a in both chains 10-15 ms longer than for native RCs and RCs that still have a BPheo in the A-chain,at all temperatures between 10 and 290 K. At low temperatures all three RC types showed biphasic P(+)Q(A)(-) recombination.

Date issued
1997-04-11
Language
English
Publisher
ELSEVIER SCIENCE BV
Is part of
Biochimica et Biophysica Acta. Bioenergetics (1997), Vol. 1319, no. 2-3, p. 242-250
hdl
1887/3590417
doi
10.1016/S0005-2728(96)00165-X