On the conformation of Phe78 of a chromoprotein antibiotic, neocarzinostatin Original Research Article

A structure of neocarzinostatin, an antitumor chromoprotein antibiotic, has been built using X-ray crystallographic data and NMR data, particularly NOE data observed between the apoprotein and the chromophore. Chemical shift changes of protons of the chromophore upon binding to the apoprotein indicated that the aromatic plane of Phe52 has the conformation almost perpendicular to the C-2C-3 triple bond of the core of the chromophore while Phe78 takes multiple conformations in solution although one of the stable conformations has been assigned for Phe78 in a crystal structure.