Design & Synthesis of Oxygen-Binding Heme Peptides
Final progress rept.
BAYLOR COLL OF MEDICINE HOUSTON TX DEPT OF BIOCHEMISTRY
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The goal of this work was to design and synthesize peptides that will form functional complexes with heme and thus have physiologically useful oxygen- binding properties. Several peptides which will mimic the natural environment of the heme group in myoglobin Mb and in the alpha- and Beta-subunits of hemoglobin Hb were proposed. The heme cavity of Mb and the alpha-and Beta- chains would be mimicked by the concept of surface-simulation synthesis into three peptides that incorporate the essential contact residues with appropriate spacing and directionality. Control peptides would also be made that have all the essential contact residues, but in a random order. Other designs were based on the fact that the heme group in the aforementioned proteins is sandwiched between helices E and F. Thus, one set of peptides would correspond to the E-F helical segment. In three other sets of peptides, parts of the E-F segment which form hair-pin-loops that fold away from the heme cavity, would be bypassed by appropriate spatial bridging. All these peptides were synthesized, purified and characterized. The free peptides, except for those peptides based on the surface-simulation design, were able to bind the heme group and form stable peptide-heme complexes. jes