▁( F b FP ), ▁also ▁known ▁as ▁a ▁LO V - based ▁flu ores cent ▁protein , ▁is ▁a ▁small , ▁o xygen - in dependent ▁flu ores cent ▁protein ▁that ▁bind s ▁fla vin ▁mon on uc le ot ide ▁( FM N ) ▁as ▁a ▁chrom oph ore . ▁ ▁They ▁were ▁developed ▁from ▁blue - light ▁re cept ors ▁( so ▁called ▁LO V - dom ains ) ▁found ▁in ▁plants ▁and ▁various ▁b acter ia . ▁They ▁complement ▁the ▁G FP - der iv atives ▁and ▁– hom olog ues ▁and ▁are ▁particularly ▁character ized ▁by ▁their ▁independence ▁of ▁mole cular ▁o xygen ▁and ▁their ▁small ▁size . ▁F b FP s ▁abs orb ▁blue ▁light ▁and ▁emit ▁light ▁in ▁the ▁cy an - green ▁spectral ▁range . ▁ ▁Development ▁ ▁LO V - dom ains ▁are ▁a ▁sub - class ▁of ▁P AS ▁domains ▁and ▁were ▁first ▁identified ▁in ▁plants ▁as ▁part ▁of ▁Phot otrop in , ▁which ▁plays ▁an ▁essential ▁role ▁in ▁the ▁plant ' s ▁growth ▁towards ▁light . ▁They ▁non c oval ently ▁bind ▁F la vin ▁mon on uc le ot ide ▁( FM N ) ▁as ▁co enz yme . ▁Due ▁to ▁the ▁bound ▁FM N ▁LO V - dom ains ▁exhib it ▁an ▁intr insic ▁flu ores c ence , ▁which ▁is ▁however ▁very ▁weak . ▁Upon ▁ill um ination ▁with ▁blue ▁light , ▁LO V - dom ains ▁under go ▁a ▁phot oc yle , ▁during ▁which ▁a ▁c oval