Structural changes accompanying electron transfer in copper(II)/copper(I) complexes involving related open-chain and cyclic tetrathia ether ligands

1985 ◽  
Vol 24 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Leonard L. Diaddario ◽  
Edward R. Dockal ◽  
Milton D. Glick ◽  
L. A. Ochrymowycz ◽  
D. B. Rorabacher
Keyword(s):  
Electron Transfer ◽  
Structural Changes ◽  
Open Chain

scholarly journals An examination of how structural changes can affect the rate of electron transfer in a mutated bacterial photoreaction centre

2000 ◽  
Vol 351 (3) ◽  
pp. 567 ◽  
Author(s):  
Justin P. RIDGE ◽  
Paul K. FYFE ◽  
Katherine E. McAULEY ◽  
Marion E. van BREDERODE ◽  
Bruno ROBERT ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Structural Changes

scholarly journals Electron-transfer‐mediated binding of optically active cobalt(III) complexes to horse heart cytochrome c

2005 ◽  
Vol 2 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Ulrich Scholten ◽  
Alejandro Castillejo Merchán ◽  
Klaus Bernauer
Keyword(s):  
Electron Transfer ◽  
Structural Changes ◽  
Electron Transfer Reaction ◽  
Optically Active ◽  
Cd Spectra ◽  
Reaction Products ◽  
Horse Heart Cytochrome ◽  
Histidine Residues ◽  
Horse Heart Cytochrome C ◽  
Haem Iron

Optically active cobalt(II) complexes are used as reducing agents in the electron-transfer reaction involving horse heart cytochrome c . Analysis of the circular dichroism (CD) spectra of reaction products indicates that the corresponding cobalt(III) species of both enantiomers of [Co II (alamp)] (H 2 alamp= N , N ′-[(pyridine-2,6-diyl)bis(methylene)]-bis[alanine]) are partly attached to the protein during electron transfer by coordination to an imidazole unit of one of the histidine residues. His-26 and His-33 are both solvent exposed, and the results suggest that one of these histidine residues acts as a bridge in the electron transfer to and from the haem iron of cytochrome c . The reaction is enantioselective: the ratio of the relative reactivity at 15 °C is 2.9 in favour of the R , R -enantiomer. A small induced CD activity in the haem chromophore reveals that some structural changes in the protein occur consecutively with the binding of the cobalt(III) complex.

scholarly journals An examination of how structural changes can affect the rate of electron transfer in a mutated bacterial photoreaction centre

2000 ◽  
Vol 351 (3) ◽  
pp. 567-578 ◽  
Author(s):  
Justin P. RIDGE ◽  
Paul K. FYFE ◽  
Katherine E. McAULEY ◽  
Marion E. VAN BREDERODE ◽  
Bruno ROBERT ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Structural Changes ◽  
Structural Model ◽  
Transient Absorption ◽  
Photosynthetic Bacterium ◽  
Primary Electron ◽  
Interface Region ◽  
Reaction Centre ◽  
Primary Donor ◽  
Out Of Plane

A series of reaction centres bearing mutations at the (Phe) M197 position were constructed in the photosynthetic bacterium Rhodobacter sphaeroides. This residue is adjacent to the pair of bacteriochlorophyll molecules (PL and PM) that is the primary donor of electrons (P) in photosynthetic light-energy transduction. All of the mutations affected the optical and electrochemical properties of the P bacteriochlorophylls. A mutant reaction centre with the change Phe M197 to Arg (FM197R) was crystallized, and a structural model constructed at 2.3 Å (1Å = 0.1nm) resolution. The mutation resulted in a change in the structure of the protein at the interface region between the P bacteriochlorophylls and the monomeric bacteriochlorophyll that is the first electron acceptor (BL). The new Arg residue at the M197 position undergoes a significant reorientation, creating a cavity at the interface region between P and BL. The acetyl carbonyl substituent group of the PM bacteriochlorophyll undergoes an out-of-plane rotation, which decreases the edge-to-edge distance between the macrocycles of PM and BL. In addition, two new buried water molecules partially filled the cavity that is created by the reorientation of the Arg residue. These waters are in a suitable position to connect the macrocycles of P and BL via three hydrogen bonds. Transient absorption measurements show that, despite an inferred decrease in the driving force for primary electron transfer in the FM197R reaction centre, there is little effect on the overall rate of the primary reaction in the bulk of the reaction-centre population. Examination of the X-ray crystal structure reveals a number of small changes in the structure of the reaction centre in the interface region between the P and BL bacteriochlorophylls that could account for this faster-than-predicted rate of primary electron transfer.

Sign in / Sign up

Export Citation Format

Share Document