title: Structural and functional characterization of Delphinus delphis hemoglobin system.
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 (beta1 16,022 Da, beta2 16,036 Da, beta3 16,036 Da, labeled according to their progressive elution times) and two major alpha globins (alpha1 15,345 Da, alpha2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that beta2 globin differs from beta1 for the substitution Val126 --> Leu, while beta3 globin differs from beta2 for the isobaric substitution Lys65 --> Gln. The alpha2 globin differs from the alpha1 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 beta1, beta2 and both the alpha globins, and the fraction with lower pI (HbII) contained beta3 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 Probeta5 --> Gly or the Probeta5 --> 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 Lysbeta65 --> Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA(0).
authors: Department of Applied Sciences to Biosystems, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, CA, Italy.
authors: Barbara
authors: B
authors: Manconi
authors: Irene
authors: I
authors: Messana
authors: Federica
authors: F
authors: Maggiani
authors: Alessandra
authors: A
authors: Olianas
authors: Mariagiuseppina
authors: M
authors: Pellegrini
authors: Roberto
authors: R
authors: Crnjar
authors: Massimo
authors: M
authors: Castagnola
authors: Bruno
authors: B
authors: Giardina
authors: Maria Teresa
authors: MT
authors: Sanna
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D050696:Common Dolphins / Q000097:blood* / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007526:Isoelectric Point; D008522:Mediterranean Sea; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D013696:Temperature
chemical_list: D018076:DNA, Complementary; D006454:Hemoglobins; D010446:Peptide Fragments; D020033:Protein Isoforms; D021122:Protein Subunits; D010100:Oxygen