The Effect of Pressure on the Bacteriochlorophyll a Binding Sites of the Core Antenna Complex from Rhodospirillum rubrum

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• 作者：James N. Sturgis ; Andrew Gall ; Aleksandr Ellervee ; Arvi Freiberg ; and Bruno Robert
• 刊名：Biochemistry
• 出版年：1998
• 出版时间：October 20, 1998
• 年：1998
• 卷：37
• 期：42
• 页码：14875 - 14880
• 全文大小：57K
• 年卷期：v.37,no.42(October 20, 1998)
• ISSN：1520-4995

文摘

In this paper we examine the effect of pressure on the absorption spectrum and binding siteof the core antenna complex from the photosynthetic bacterium Rhodospirillum rubrum. Absorption spectraand Raman spectra in preresonance with the Q_y transition of the bacteriochlorophyll a were studied atpressures up to 625 MPa. In agreement with previous work we observe a pressure-induced red shift andbroadening of the absorption spectrum. We show that at these pressures the pigments within the proteinmatrix at room temperature experience little if any distortion, and the hydrogen-bonding network involvingthe C₂ and C₉ carbonyl groups of the pigment molecules are undisturbed. Having shown the lack ofsensitivity to pressure of the binding site interactions, which are known to modulate the absorption spectrum,we feel that it is relatively safe to attribute the pressure-induced red shift broadly to solvatochromic effectsand, in particular, to the modulation of the pigment-pigment interactions by the pressure. This paperrepresents the first vibrational study of photosynthetic complexes at high pressure and the first applicationof FT Raman spectroscopy to biological molecules at high pressure.