An extremely stable Ni(II) complex derived from the hydrolytic cleavage of the C-terminal tail of histone H2A
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Mylonas, M.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
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Mylonas, M.
(EN)
The C-terminal blocked tetrapeptides SHHK- and SAHK-, which represent the fragments produced from the hydrolysis of the hexapeptides' -TASHHK-, -TESHHK-, and -TESAHK- complexes with Ni(II), were synthesized and their interactions with Ni(II) ions were studied potentiometrically and spectroscopically. Both tetrapeptides interact strongly with Ni(II) ions leading to square-planar complexes with 4N {NH2,2N(-),N-im} coordination. The stability of the Ni-SHHK- complex is about 2 orders of magnitude higher than the Ni-SAHK- complex. Spectroscopic evidence and theoretical predictions suggest the positioning of the free imidazole ring, in the Ni-SHHK- complex, above the coordination plane, explaining the extra stability of the complex. (C) 2004 Elsevier Inc. All rights reserved.
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