Reconstitution of apomyoglobin with bile pigments

Summary Apomyoglobin was reconstituted with bile pigments of the verdinoid, 2,3-dihydroverdinoid, pterobilinoid, and violinoid type. Absorption and circular dichroism data as well as formation constants of the complexes were measured. From these results it was concluded that chromophore binding and induced chirality of these pigments are mainly governed by a lipophilic region opposite to the propionic side chain(s) and the asymmetric position of the hydrogen bonding acceptors of the propionic acid side chain(s) at the entrance of the protein pocket.Dedicated to Prof. Dr. A. Eschenmoser on occasion of his 65th birthday     

Complex formation between biliverdin and apomyoglobin

Summary The intermolecular interactions of biliverdin with apomyoglobin were investigated using UV-VIS spectroscopy and chiroptical methods. Biliverdin is bound reversibly in the heme pocket of the apoprotein. The structural implications of the spectroscopic findings are discussed.

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Komplexbildung zwischen Biliverdin und Apomyoglobin

Zusammenfassung Die intermolekularen Wechselwirkungen von Biliverdin mit Apomyoglobin wurden mittels UV-VIS-Spektroskopie und chiroptischen Methoden untersucht. Biliverdin wird reversibel in der Häm-Tasche des Apoproteins gebunden. Strukturelle Implikationen der spektroskopischen Resultate werden diskutiert.

     

On the chemistry of pyrrole pigments,LXXXVII: The apomyoglobin heme pocket as a reaction vessel in bile pigment chemistry

Summary An apomyoglobin biliverdin complex was reduced to a bilirubin apomyoglobin complex with retention of the helix chirality of the chromophore. Chelation of the mesobiliverdin-XIII apomyoglobin complex with zinc ions in aqueous solution yielded an enantiomer of the corresponding derivative. These two systems document the possibility of using the heme pocket of apomyoglobin to execute stereospecific reactions. The chiroptical properties of the two product systems are discussed.

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Zur Chemie von Pyrrolpigmenten, 87. Mitt.: Die Häm-Tasche des Apomyoglobins als Reaktionsgefäß für die Chemie von Gallenfarbstoffen

Zusammenfassung Der Apomyoglobin-Biliverdin-Komplex wurde zum entsprechenden Apomyoglobin-Bilirubin-Komplex unter Retention der Helixkonfiguration des Chromophors reduziert. Chelierung des Apomyoglobin-Mesobiliverdin-XIII-Komplexes mit Zinkionen in wäßriger Lösung lieferte ein Enantiomer des entsprechenden Derivates. Diese beiden Systeme dokumentieren die Verwendbarkeit der Häm-Tasche des Apomyoglobins um stereospezifische Reaktionen durchzuführen. Die chiroptischen Eigenschaften der beiden Produktsysteme werden diskutiert.

     

Proteolytic Preparation of a Heme Binding Fragment from Sperm Whale Myoglobin: Micro-Myoglobin

Summary.  Clostripain digestion of sperm whale apomyoglobin does not yield a heme binding fragment, contrary to horse heart apomyoglobin, from which mini-myoglobin has been obtained by this approach. However, in pepsin digests of sperm whale apomyoglobin we identified two fragments closely corresponding to the polypeptide encoded by the central exon of the myoglobin gene. One of these fragments consisting of 77 amino acid residues was purified. Spectroscopic data indicate that it has heme binding properties. Received October 28, 1999. Accepted November 23, 1999