Structural analysis of the hemoglobin (Hb) system of Delphinus delphis revealed a high globin multiplicity: HPLC-electrospray ionization-mass spectrometry (ESI-MS) analysis evidenced three major beta (beta 1 16,022 Da, beta 2 16,036 Da, beta 3 16,036 Da, labeled according to their progressive elution times) and two major alpha globins (alpha 1 15,345 Da, alpha 2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that beta 2 globin differs from beta 1 for the substitution Val126 -> Leu, while beta 3 globin differs from beta 2 for the isobaric substitution Lys65 -> Gln. The alpha 2 globin differs from the alpha 1 for the substitution Ser15 -> Ala. Anion-exchange chromatography allowed the separation of two Hb fractions and HPLC-ESI-MS analysis revealed that the fraction with higher pI (HbI) contained beta 1, beta 2 and both the alpha globins, and the fraction with lower pI (HbII) contained beta 3 and both the alpha globins. Both D. delphis Hb fractions displayed a lower intrinsic oxygen affinity, a decreased effect of 2,3-BPG and a reduced cooperativity with respect to human HbA(0), with HbII showing the more pronounced differences. With respect to HbA(0), either the substitution Pro beta 5 -> Gly or the Pro beta 5 -> Ala is present in all the cetacean beta globins sequenced so far, and it has been hypothesized that position 5 of beta globins may have a role in the interaction with 2,3-BPG. Regarding the particularly lowered cooperativity of HbII, it is interesting to observe that the variant human HbA, characterized by the substitution Lys beta 65 -> Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA(0).
Manconi, B., Messana, I., Maggiani, F., Olianas, A., Pellegrini, M., Crnjar, R., Castagnola, M., Giardina, B., Sanna, M., Structural and functional characterization of Delphinus delphis hemoglobin system, <<JOURNAL OF COMPARATIVE PHYSIOLOGY. B, BIOCHEMICAL, SYSTEMIC, AND ENVIRONMENTAL PHYSIOLOGY>>, 2009; 179 (8): 971-983. [doi:10.1007/s00360-009-0380-2] [http://hdl.handle.net/10807/26026]
Structural and functional characterization of Delphinus delphis hemoglobin system
Castagnola, Massimo;Giardina, Bruno;
2009
Abstract
Structural analysis of the hemoglobin (Hb) system of Delphinus delphis revealed a high globin multiplicity: HPLC-electrospray ionization-mass spectrometry (ESI-MS) analysis evidenced three major beta (beta 1 16,022 Da, beta 2 16,036 Da, beta 3 16,036 Da, labeled according to their progressive elution times) and two major alpha globins (alpha 1 15,345 Da, alpha 2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that beta 2 globin differs from beta 1 for the substitution Val126 -> Leu, while beta 3 globin differs from beta 2 for the isobaric substitution Lys65 -> Gln. The alpha 2 globin differs from the alpha 1 for the substitution Ser15 -> Ala. Anion-exchange chromatography allowed the separation of two Hb fractions and HPLC-ESI-MS analysis revealed that the fraction with higher pI (HbI) contained beta 1, beta 2 and both the alpha globins, and the fraction with lower pI (HbII) contained beta 3 and both the alpha globins. Both D. delphis Hb fractions displayed a lower intrinsic oxygen affinity, a decreased effect of 2,3-BPG and a reduced cooperativity with respect to human HbA(0), with HbII showing the more pronounced differences. With respect to HbA(0), either the substitution Pro beta 5 -> Gly or the Pro beta 5 -> Ala is present in all the cetacean beta globins sequenced so far, and it has been hypothesized that position 5 of beta globins may have a role in the interaction with 2,3-BPG. Regarding the particularly lowered cooperativity of HbII, it is interesting to observe that the variant human HbA, characterized by the substitution Lys beta 65 -> Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA(0).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.