Substitution of Isoleucine M206 Residue by Histidine in the Rhodobacter sphaeroides Reaction Centers Causes Changes in the Structure of the Special Bacteriochlorophyll Pair Molecule

Bolgarina, T. I.; Khatypov, R. A.; Васильева, Л.Г.; Shkuropatov, A. Ya.; Shuvalov, Vladimir V

doi:10.1023/b:dobi.0000017147.33235.b4

Cited by 5 publications

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“…sphaeroides RC mutant having Ile M206 substituted by His in the vicinity of the special pair BChl [5]. This muta tion lead to drastic changes of the RC spectral and photo chemical properties, and the quantum yield of the charge separation was significantly decreased.…”

Section: Resultsmentioning

confidence: 99%

“…Such alterations introduced by site directed mutagenesis allow investigation of how the protein environment of chro mophores influences the efficiency and directionality of the primary charge separation and stabilization in bacter ial photosynthesis [4]. In our previous paper [5], it was shown that after the substitution of Ile M206 by His the pigment composition of RC was altered. Namely, in the mutant RC some structural changes in one out of four BChl molecules were suggested.…”

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Substitution of Isoleucine L177 by Histidine Affects the Pigment Composition and Properties of the Reaction Center of the Purple Bacterium Rhodobacter sphaeroides

Khatypov

Vasilieva

Fufina

et al. 2005

Biochemistry (Moscow)

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Using site-directed mutagenesis, we obtained the mutant of the purple bacterium Rhodobacter sphaeroides with Ile to His substitution at position 177 in the L-subunit of the photosynthetic reaction center (RC). The mutant strain forms stable and photochemically active RC complexes. Relative to the wild type RCs, the spectral and photochemical properties of the mutant RC differ significantly in the absorption regions corresponding to the primary donor P and the monomer bacteriochlorophyll (BChl) absorption. It is shown that the RC I(L177)H contains only three BChl molecules compared to four BChl molecules in the wild type RC. Considering the fact that the properties of both isolated and membrane-associated mutant RCs are similar, we conclude that the loss of a BChl molecule from the mutant RC is caused by the introduced mutation but not by the protein purification procedure. The new mutant missing one BChl molecule but still able to perform light-induced reactions forming the charge-separated state P+QA- appears to be an interesting object to study the mechanisms of the first steps of the primary electron transfer in photosynthesis.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Substitution of Isoleucine L177 by Histidine Affects the Pigment Composition and Properties of the Reaction Center of the Purple Bacterium Rhodobacter sphaeroides

Khatypov

Vasilieva

Fufina

et al. 2005

Biochemistry (Moscow)

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The L(M196)H mutation in Rhodobacter sphaeroides reaction center results in new electrostatic interactions

et al. 2014

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New histidine residue was introduced in M196 position in the reaction center of Rhodobacter sphaeroides in order to alter polarity of the BChl dimer's protein environment and to study how it affects properties and structure of the primary electron donor P. It was shown that in the absorption spectrum of the mutant RC the 6 nm red shift of the Q Y P band was observed together with considerable decrease of its amplitude. The mid-point potential of P/P (+) in the mutant RC was increased by +65 (±15) mV as compared to the E m P/P (+) value in the wild-type RC suggesting that the mutation resulted in new pigment-protein interactions. Crystal structure of RC L(M196)H determined at 2.4 Å resolution implies that BChl Р В and introduced histidine-M196 organize new electrostatic contact that may be specified either as π-π staking or as hydrogen-π interaction. Besides, the structure of the mutants RC shows that His-M196 apparently became involved in hydrogen bond network existing in BChl Р В vicinity that may favor stability of the mutant RC.

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Structure-function investigations of bacterial photosynthetic reaction centers

Leonova

Fufina

Vasilieva

et al. 2011

Biochemistry Moscow

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During photosynthesis light energy is converted into energy of chemical bonds through a series of electron and proton transfer reactions. Over the first ultrafast steps of photosynthesis that take place in the reaction center (RC) the quantum efficiency of the light energy transduction is nearly 100%. Compared to the plant and cyanobacterial photosystems, bacterial RCs are well studied and have relatively simple structure. Therefore they represent a useful model system both for manipulating of the electron transfer parameters to study detailed mechanisms of its separate steps as well as to investigate the common principles of the photosynthetic RC structure, function, and evolution. This review is focused on the research papers devoted to chemical and genetic modifications of the RCs of purple bacteria in order to study principles and mechanisms of their functioning. Investigations of the last two decades show that the maximal rates of the electron transfer reactions in the RC depend on a number of parameters. Chemical structure of the cofactors, distances between them, their relative orientation, and interactions to each other are of great importance for this process. By means of genetic and spectral methods, it was demonstrated that RC protein is also an essential factor affecting the efficiency of the photochemical charge separation. Finally, some of conservative water molecules found in RC not only contribute to stability of the protein structure, but are directly involved in the functioning of the complex.

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Substitution of Isoleucine M206 Residue by Histidine in the Rhodobacter sphaeroides Reaction Centers Causes Changes in the Structure of the Special Bacteriochlorophyll Pair Molecule

Cited by 5 publications

References 5 publications

Substitution of Isoleucine L177 by Histidine Affects the Pigment Composition and Properties of the Reaction Center of the Purple Bacterium Rhodobacter sphaeroides

Substitution of Isoleucine L177 by Histidine Affects the Pigment Composition and Properties of the Reaction Center of the Purple Bacterium Rhodobacter sphaeroides

The L(M196)H mutation in Rhodobacter sphaeroides reaction center results in new electrostatic interactions

Structure-function investigations of bacterial photosynthetic reaction centers

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