Figure 1. Investigation and classification of heme-binding sequences by means of a combinatorial peptide library.

(A) A combinatorial peptide library X₄(C/H/Y)⁰X₄ was constructed in order to investigate sequence specificities of heme-binding peptides. As a result of the screening, a classification system for HRMs/HBMs (B) was compiled for cysteine-, histidine-, and tyrosine-based motifs including extra classes for CP motifs [13,29,33,34].