crosslinked residues coelenterazine -50.036777496337890625 -50.060001373291015625 423.158294677734375 423.470001220703125 8-benzyl-2-(4-hydroxybenzyl)-6-(4-hydroxyphenyl)imidazo[1,2-a]pyrazin-3(7H)-one A protein modification that effectively cross-links a phenylalanine and two tyrosine residues to form coelenterazine. C -1 H -6 N 0 O -2 C 26 H 21 N 3 O 3 Cross-link 3. F, Y, Y MOD:01949 N-term Oplophorus luciferin PSI-MOD coelenterazine hypothetical crosslinked L-phenylalanine residue crosslinked L-tyrosine residue