Maria Teresa Sanna, Barbara Manconi, Gabriella Podda, Alessandra Olianas, Mariagiuseppina Pellegrini, Massimo Castagnola, Irene Messana, Bruno Giardina
Alkaline Bohr effect of bird hemoglobins: the case of the flamingo
The substitution His?Gln at position ?89, very common in avian Hbs, is considered
responsible for the weak Bohr effect of avian Hbs. Phoenicopterus ruber ruber is one of the
few avian Hb that possess an His at ?89, but its functional characterization has not been
performed yet. In the present study the Hb system of the greater flamingo (P. ruber roseus), a
bird that lives in Mediterranean areas, has been investigated in order to obtain further insight
into the role played by ?89 residue in determining the strong reduction of the Bohr effect.
The functional analysis performed on the two purified Hb components (HbA and HbD) of P.
ruber roseus showed that both are characterized by a high oxygen affinity in the absence of
organic phosphates, a strong modulating effect of inositol hexaphosphate, and a reduced Bohr
effect. Indeed, in spite of the close phylogenetic relationship between the two flamingo species,
the structural analysis carried out by tandem mass spectrometry on the ?A chain of P. ruber
roseus showed that a Gln residue is present at position α89.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 2007
Pages: -
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