It has been thought for several years that the greatly lowered oxygen affinity, high cooperativity, and heterotropic modulation displayed by tetrameric human hemoglobin (Hb) was an exclusive result of the assembly of high affinity α1β1 dimers into α2β2 tetramers. However, in recent times, it has been shown that α- and β-semihemoglobins, namely α(heme)β(apo) and α(apo)β(heme), which are dimers of Hb characterized by a high affinity for oxygen and lack of cooperativity do respond to effectors such as 2-[4-(3,5-dichlorophenylureido) phenoxy]-2-methylpropionic acid (L35), a bezafibrate (BZF) related compound, by decreasing the ligand affinity to a considerable extent (between 60- and 130-fold). In order to shed some light on the structural basis of this phenomenon, we have developed a binding mode of L35 to semihemoglobins through docking analysis using the program GRID. Molecular modelling studies did identify sites on semihemoglobins where favourable interactions with L35 can occur. We found that the effector binds differently to the two semihemoglobins exhibiting high affinity only for the α chain heme pocket. The proposed binding models are consistent with the experimental findings and may be rationalized in terms of different hydrophobic and hydrophilic characteristics between α- and β-heme pockets of Hb.

De Rosa, M., Carelli Alinovi, C., Russo, A., Giardina, B., Binding modes of L35 to alpha- and beta-semihemoglobins: structural insights into the inequivalence of alpha- and beta-subunits of hemoglobin, <<BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS>>, 2007; (Marzo): 720-726 [http://hdl.handle.net/10807/62145]

Binding modes of L35 to alpha- and beta-semihemoglobins: structural insights into the inequivalence of alpha- and beta-subunits of hemoglobin

Carelli Alinovi, Cristiana;Giardina, Bruno
2007

Abstract

It has been thought for several years that the greatly lowered oxygen affinity, high cooperativity, and heterotropic modulation displayed by tetrameric human hemoglobin (Hb) was an exclusive result of the assembly of high affinity α1β1 dimers into α2β2 tetramers. However, in recent times, it has been shown that α- and β-semihemoglobins, namely α(heme)β(apo) and α(apo)β(heme), which are dimers of Hb characterized by a high affinity for oxygen and lack of cooperativity do respond to effectors such as 2-[4-(3,5-dichlorophenylureido) phenoxy]-2-methylpropionic acid (L35), a bezafibrate (BZF) related compound, by decreasing the ligand affinity to a considerable extent (between 60- and 130-fold). In order to shed some light on the structural basis of this phenomenon, we have developed a binding mode of L35 to semihemoglobins through docking analysis using the program GRID. Molecular modelling studies did identify sites on semihemoglobins where favourable interactions with L35 can occur. We found that the effector binds differently to the two semihemoglobins exhibiting high affinity only for the α chain heme pocket. The proposed binding models are consistent with the experimental findings and may be rationalized in terms of different hydrophobic and hydrophilic characteristics between α- and β-heme pockets of Hb.
Inglese
De Rosa, M., Carelli Alinovi, C., Russo, A., Giardina, B., Binding modes of L35 to alpha- and beta-semihemoglobins: structural insights into the inequivalence of alpha- and beta-subunits of hemoglobin, <<BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS>>, 2007; (Marzo): 720-726 [http://hdl.handle.net/10807/62145]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/62145
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact