Engineering Ascaris hemoglobin oxygen affinity in sperm whale myoglobin: role of tyrosine B10

FEBS Letters

Brancaccio, Andrea¹  Cutruzzolà, Francesca¹  Brunori, Maurizio¹  Vallone, Beatrice¹  Allocatelli, Carlo Travaglini¹ 

[1]Department of Biochemical Sciences ‘A. Rossi Fanelli’ and CNR Centre for Molecular Biology, University of Rome ‘La Sapienza’, P.le A. Moro 5, 00185 Rome, Italy

关键词: Myoglobin;    Protein engineering;    Oxygen affinity;    Hydrogen bond;    s.w.;    sperm whale;    Mb;    myoglobin;    Hb;    hemoglobin. Each protein is identified by the one-letter code for the residues in positions B10;    E7 and E10;    respectively;    these are capital letters for wild type residues (e.g. wild type Mb = Leu(B10)/His(E7)/Thr(E10) = LHT) and capital bold for the mutated residues (e.g. Leu(B10)/His(E7) → Gln/ Thr(E10) = LQT);   

DOI  :  10.1016/0014-5793(94)00918-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The contribution to oxygen stabilization of a tyrosine residue in topological position (B10) has been studied in sperm whale myoglobin by simultaneous replacement of residues at positions (B10), (E7) and (E10) as suggested by analysis of the sequence of high oxygen affinity hemoglobins, such as that of the nematode Ascaris suum. Kinetic and equilibrium experiments with the gaseous ligands oxygen and carbon monoxide show that indeed the introduction of tyrosine (B10), together with replacement of the distal histidine (E7) with glutamine, is associated with a large decrease in the oxygen dissociation rate constant. Our results are consistent with the possible formation in the distal pocket of two hydrogen bonds with the iron-bound oxygen.

【 授权许可】

Unknown