Book of Abstracts - Ruhr-Universität Bochum

P-60
ISBOMC `10 5.7 – 9.7. 2010 Ruhr-Universität Bochum
Exploring Histidines as Biomolecular Anchors to Re(CO)3 +
Richard S. Herrick, a Christopher J. Ziegler, b Roger Rowlett, Americo Gambella a
a College of the Holy Cross, Department of Chemistry, 1 College St., Worcester, MA 01610, USA.
b University of Akron, Department of Chemistry, KNCL 402, Akron, OH 444325, USA. c Department
of Chemistry, Colgate University, 13 Oak Drive, Hamilton, NY 13346 (USA).
E-mail: rherrick@holycross.edu
In recent years we have explored the potential of using amino acids and amino acid conjugates to bind
Re(CO)3 + . We are currently exploring the use of histidine-containing peptide conjugates as models of
His-tags in order to test their ability to bind the Re(CO)3 + . His-OMe, Ac-His-OH and His-His-OH
were each exposed to aqueous solution of Re(CO)3 + . Reaction with His-OMe lead to ester cleavage
and formation of the previously observed Re(CO)3(� 3 -N�,N�,O - -His). Reactions with Ac-His-OH and
His-His-OH each led to novel compounds containing a carboxamido N-donor group. The
characterization, including X-ray crystallography, of each compound, and testing of each compounds
ability to withstand challenge experiments will be discussed.
We have also been interested in using proteins to bind Re(CO)3 + . Little work has been carried out on
reactions between rhenium prodrug or drug model complexes and proteins. Such interactions can be
crucial to the biological processing of Tc/Re based imaging agents, since proteins, rather than
nucleotides or single amino acids, would be encountered in plasma. Alternatively, protein-Tc/Re
adducts could be novel targets for use as imaging or therapeutic agents. In order to probe this
chemistry, we are examining the interactions between Re(CO)3(H2O)3 + and the readily crystallizable
protein lysozyme. A crystal structure has been obtained of a lysozyme-Re(CO)3(H2O)2 adduct.
Experimental details, including the new crystal structure, will be discussed.
From these studies highlighting the binding of histidines in peptides and proteins to Re(CO)3(H2O)3 + ,
several conclusions can be drawn. These will be discussed along with future directions of this
research.
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