The nonplanar conformations oftetrapyrrole pigments in photosynthetic reaction center complexes availablefrom the protein databank have been studied using normal structuraldecomposition and multivariant analyses. Three major conserved conformations werefound across most bacterial reaction centers: 1) the accessory pigments of theETC; 2) the �L� member of the special pair and 3) the �R� member of the specialpair. Detailed inspection of the relative spatial distribution of the nonplanardeformations showed possible trends that show a gradual variation of specificdeformations within functional classes. This implies that theprotein-macrocycle interaction ensures a smooth transition between deformations,possibly in order to modulate functional efficiency. The results indicate thatsuch analyses may be a general means to study the functionality ofporphyrin-containing functional systems. The conformation of the macrocycle is akey factor in these systems as is the relative positioning of conformations inthe electron transfer chain of photosynthesis.

Conformational control
of cofactors in nature: Conservation of tetrapyrrole conformations in the
photosynthetic reaction centers of purple bacteria

242nd National Meeting (2011)

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Conformational control of cofactors in nature: Conservation of tetrapyrrole conformations in the photosynthetic reaction centers of purple bacteria