Construction and characterization of a chimeric myoglobin.
In order to investigate the functional and structural role of modular structure in globins, we have engineered a chimeric myoglobin (ChimMb) in which the first and third exon come from the gene coding for the sperm whale Mb and the second exon from the gene coding for Aplysia limacina Mb. This ChimMb, fused to the Maltose Binding Protein (MBP) and expressed in Escherichia coli as an apoprotein, binds protoheme in a 1:1 stoichiometric ratio. Based on some functional and spectroscopic properties, we conclude that the central core of the ChimMb (which derives from A. limacina) is native-like. On the other hand, the ChimMb deprived (by proteolytic digestion) of the fused MBP displays a considerably reduced stability. These results suggest that the sperm whale A-G-H nucleus does not contribute significantly to the overall stability of the ChimMb.
Musto
Raffaella
R
Dipartimento di Scienze Biochimiche "A Rossi Fanelli", Università di Roma "La Sapienza", Piazzale Aldo Moro 5, I-00185, Rome, Italy.
Brunori
Maurizio
M
Cutruzzolà
Francesca
F
Travaglini-Allocatelli
Carlo
C
D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics; D002942:Circular Dichroism; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D005091:Exons; D006427:Hemin / Q000737:chemistry; D007544:Isopropyl Thiogalactoside; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D014907:Whales / Q000235:genetics*
D002352:Carrier Proteins; D058619:Maltose-Binding Proteins; D009211:Myoglobin; D011993:Recombinant Fusion Proteins; D007544:Isopropyl Thiogalactoside; D006427:Hemin