7dgk | pdb_00007dgk

The Co-bound dimeric structure of K78H/G80A/H82A myoglobin

spinqualitylabelsall models 7dgk, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7dgk is a 2 chain structure with sequence from Equus caballus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CO, HEM, O Gene: MB (Equus caballus) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [MYG_HORSE] Serves as a reserve supply of oxygen and facilitates the movement of oxygen within muscles. Publication Abstract from PubMed The metal active site is precisely designed in metalloproteins. Here we applied 3D domain swapping, a phenomenon in which a partial protein structure is exchanged between molecules, to introduce metal sites in proteins. We designed multiple metal-binding sites specific to domain-swapped myoglobin (Mb) with His mutation. Stable dimeric Mbs with metal-binding sites were obtained by shifting the His position and introducing two Ala residues in the hinge region (K78H/G80A/H82A and K79H/G80A/H81A Mbs). The absorption and circular dichroism spectra of the monomer and dimer of K78H/G80A/H82A and K79H/G80A/H81A Mbs were similar to the corresponding spectra, respectively, of wild-type Mb. No negative peak due to dimer-to-monomer dissociation was observed below the denaturation temperature in the differential scanning calorimetry thermograms of K78H/G80A/H82A and K79H/G80A/H81A Mbs, whereas the dimer dissociates into monomers at 68 degrees C for wild-type Mb. These results show that the two mutants were stable in the dimer state. Metal ions bound to the metal-binding sites containing the introduced His in the domain-swapped Mb dimers. Co(2+)-bound and Ni(2+)-bound K78H/G80A/H82A Mb exhibited octahedral metal-coordination structures, where His78, His81, Glu85, and three H2O/OH(-) molecules coordinated to the metal ion. On the other hand, Co(2+)-bound and Zn(2+)-bound K79H/G80A/H81A Mb exhibited tetrahedral metal-coordination structures, where His79, His82, Asp141, and a H2O/OH(-) molecule coordinated to the metal ion. The Co(2+)-bound site exists deep inside the protein in the K79H/G80A/H81A Mb dimer, which may allow the unique tetrahedral coordination for the Co(2+) ion. These results show that we can utilize domain swapping to construct artificial metalloproteins. Rational design of metal-binding sites in domain-swapped myoglobin dimers.,Nagao S, Idomoto A, Shibata N, Higuchi Y, Hirota S J Inorg Biochem. 2021 Jan 28;217:111374. doi: 10.1016/j.jinorgbio.2021.111374. PMID:33578251 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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