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Conformational studies on Cu(II) polycomplexes of pyridoxal Schiff bases of polypeptides

✍ Scribed by M. Dentini; M. Savino; P. De Santis; A. S. Verdini

Publisher: Wiley (John Wiley & Sons)
Year: 1978
Tongue: English
Weight: 490 KB
Volume: 17
Category: Article
ISSN: 0006-3525
DOI: 10.1002/bip.1978.360170409

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✦ Synopsis

Structures of Cu(I1) complexes of pyridoxal Schiff bases with poly(L-lysine), poly(L-ornithine), and poly(L-a,?-diaminobutyric acid) were investigated by absorption spectra, CD, and conformational analysis.

Although the polypeptides retain their typical right-handed a-helical conformation, opposite Cotton effects were found for the poly(L-lysine) and poly(L-ornithine) polycomplexes in the whole range of wavelengths from 600 to 250 nm. As in the analogous derivatives of salicylaldehyde, this effect seems to be due to a stereospecific binding of the square planar Cu(I1)bis-pyridoxylideneimine group to the a-helical matrix. Circular dichroism spectrum of poly(L-a,?-diaminobutyric acid) polycomplex is similar to that found for poly(L-lysine) derivative, but indicates larger tetrahedral distortion of the square-planar coordination of copper ion.

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