Switching metalloporphyrin binding specificity of a b-type cytochrome to fluorogenic zinc by design

Abstract

Metalloporphyrins play important roles in areas ranging from biology to nanoscience. Biology uses a narrow set of metal centres comprising mainly of iron and magnesium. Here, we convert metalloporphyrin specificity of cytochrome b562 from iron (haem) to fluorogenic zinc protoporphyrin IX (ZnPP). Through a computationally guided iterative design process, a variant with a near total preference for ZnPP was generated representing a switch in specificity. The new variant greatly enhanced ([≥]60 fold) the negligible aqueous fluorescence of free ZnPP in vitro and in vivo. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/832923v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@47582aorg.highwire.dtl.DTLVardef@1ed5ec7org.highwire.dtl.DTLVardef@e9922corg.highwire.dtl.DTLVardef@7b9dbd_HPS_FORMAT_FIGEXP M_FIG C_FIG