Table 1.

Structural properties defining the state nomenclature

Protein	Conditions/temperature	Quaternary structure	LXPXRSF conformation	Secondary structure (PHY-tongue)	Cysteine linkage to chromophore (53)	Chromophore configuration	State nomenclature
Agp1	Dark/20 °C	Dimer	Elongated	β-Hairpin/sheet	β-Side	ZZZssa	Pr
	Light/−25 °C	Dimer	N.E.E.a	β-Hairpin/sheet	α-Side	ZZEssa, deprotonated	Meta-Rc
	Light/20 °C	Dimer	α-Helix	Disordered/α-helix	α-Side (N.E.E.)	ZZEssa, protonated	Pfr
IsPadC PG	Dark/20 °C	Mixture mono/dimer			β-Side	ZZZssa	Pr
	Light/−25 °C	Mixture mono/dimer	N.E.E.		α-Side	ZZEssa, protonated	Pfr-like
	Light/20 °C	Mixture mono/dimer	LXPXRSF mimic contact		α-Side	ZZEssa, protonated	Pfr-like
IsPadC	Dark/20 °C	Dimer	Elongated	β-Hairpin/sheet	β-Side	ZZZssa	Pr
	Light/−25 °C	Dimer	N.E.E.	β-Hairpin/sheet	α-Side	ZZEssa, protonated	Pfr-like
	Light/20 °C	Dimer	α-Helix or unstructured	Disordered/mixed α-helix and unstructured tongue heterodimers	α-Side	ZZEssa, protonated	Pfr-like/Pfr

^a N.E.E. means no experimental evidence.