I have no idea if the Au center bound to a porphyrin can still bind oxygen, like iron bound to heme does in hemoglobin, probably not. But one of the compounds, the green one (HAZMONHAZMOM) has a chloride bound to Au. So I wildly speculate a similar structure could be useful to some organism with a exotic biochemistry, that somehow breathes chlorine instead of oxygen.
I have no idea if the Au center bound to a porphyrin can still bind oxygen, like iron bound to heme does in hemoglobin, probably not. But one of the compounds, the green one (HAZMON) has a chloride bound to Au. So I wildly speculate a similar structure could be useful to some organism with a exotic biochemistry, that somehow breathes chlorine instead of oxygen.
I have no idea if the Au center bound to a porphyrin can still bind oxygen, like iron bound to heme does in hemoglobin, probably not. But one of the compounds, the green one (HAZMOM) has a chloride bound to Au. So I wildly speculate a similar structure could be useful to some organism with a exotic biochemistry, that somehow breathes chlorine instead of oxygen.
Most compounds of gold (Au) bound to a porphyrin recorded in the CCDC database are red, followed by orange and brown, as shown in the table:
SHORT IDENTIFIER COLOR FORMULA CHEMICAL NAME REFERENCE URL JOURNAL AUTHORS
GAFTAI Red C8 N4 Pt1 S4 2-,2(C44 H28 Au1 N4 1+) bis(Dithiomaleonitrilo-S,S')-platinum(ii) bis(tetraphenylporphyrinato-gold(iii)) Not informed Mem.Fac.Sci.Kyushu U.,Ser.C Zhung Jin Zhong; Y.Nishida; H.Okawa; S.Kida
GUTVAT Red C68 H44 Au1 N4 1+,Cl1 1-,C3 H7 N1 O1 (5,10,15,20-tetrakis(Biphenyl-4-yl)porphyrinato)-gold(iii) chloride dimethylformamide solvate http://dx.doi.org/10.1002/chem.200902741 Chem.-Eur.J. R.W.-Y.Sun; C.K.-L.Li; Dik-Lung Ma; J.J.Yan; Chun-Nam Lok; Chung-Hang Leung; Nianyong Zhu; Chi-Ming Che
GUTVEX Red C44 H24 Au1 F4 N4 1+,Au1 Cl2 1- (5,10,15,20-tetrakis(4-Fluorophenyl)porphyrinato)-gold(iii) dichloro-gold(i) http://dx.doi.org/10.1002/chem.200902741 Chem.-Eur.J. R.W.-Y.Sun; C.K.-L.Li; Dik-Lung Ma; J.J.Yan; Chun-Nam Lok; Chung-Hang Leung; Nianyong Zhu; Chi-Ming Che
KOLWOA Red C38 H9 Au1 F15 N4 1+,Cl1 1-,C1 H2 Cl2 (5,10,15-tris(pentafluorophenyl)porphyrinato)-gold(iii) chloride dichloromethane solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
KOLWUG Red C44 H8 Au1 F20 N4 1+,4(C1 H1 Cl3),Cl1 1- [5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato]-gold(iii) chloride chloroform solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
KOLXAN Red C44 H8 Au1 F20 N4 1+,0.61(C2 H4 Cl2),B1 F4 1- [5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato]-gold(iii) tetrafluoroborate 1,2-dichloroethane solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
KOLXER Red C32 H10 Au1 F10 N4 1+,0.5(C2 H4 Cl2),F6 P1 1- [5,15-bis(pentafluorophenyl)porphyrinato]-gold(iii) hexafluorophosphate 1,2-dichloroethane solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
KOLXIV Red C38 H9 Au1 F15 N4 1+,F6 P1 1-,1.46(C1 H2 Cl2) [5,10,15-tris(pentafluorophenyl)porphyrinato]-gold(iii) hexafluorophosphate dichloromethane solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
KOLXUH Red C44 H8 Au1 F20 N4 1+,C10 N5 1- [5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato]-gold(iii) pentacyanocyclopentadienide http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
ROBTOU Red C44 H28 Au1 N4 1+,C1 H1 Cl3,Cl1 1- (5,10,15,20-tetraphenylporphyrinato)-gold chloride chloroform solvate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
ROBTUA Red C44 H28 Au1 N4 1+,4(C1 H1 Cl3),Cl1 1- (5,10,15,20-tetraphenylporphyrinato)-gold chloride chloroform solvate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
ROBVAI Red C44 H28 Au1 N4 1+,B1 F4 1-,C1 H2 Cl2 (5,10,15,20-tetraphenylporphyrinato)-gold tetrafluoroborate dichloromethane solvate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
ROBVEM Red C44 H28 Au1 N4 1+,C2 H4 Cl2,F6 P1 1- (5,10,15,20-tetraphenylporphyrinato)-gold hexafluorophosphate 1,2-dichloroethane solvate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
ROBVIQ Red C44 H28 Au1 N4 1+,C10 N5 1-,0.416(C2 H4 Cl2),C2 H3 N1,0.5(H2 O1) (5,10,15,20-tetraphenylporphyrinato)-gold pentacyanocyclopentadienide acetonitrile 1,2-dichloroethane solvate hemihydrate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
FUJFEV Orange C44 H28 Au1 N4 1+,Au1 Cl4 1- (5,10,15,20-Tetraphenylporphinato-N,N',N'',N''')-gold(iii) tetrachloro-gold(iii) http://dx.doi.org/10.1107/S0108270187089789 Acta Crystallogr.,Sect.C:Cryst.Struct.Commun. A.M.Schacter; E.B.Fleischer; R.C.Haltiwanger
KOLXOB Orange C32 H10 Au1 F10 N4 1+,C10 N5 1-,C4 H8 O1 [5,15-bis(pentafluorophenyl)porphyrinato]-gold(iii) pentacyanocyclopentadienide tetrahydrofuran solvate http://dx.doi.org/10.1002/asia.201900422 Chem.Asian J. H.Tanaka; Y.Haketa; N.Yasuda; H.Maeda
HAZMOM Green C112 H112 Au1 Cl1 N8,2(C1 H1 Cl3),C3 H8 O1 (2,3,9,10,16,17,23,24-octakis(4-t-butylphenyl)phthalocyaninato)-chloro-gold(iii) chloroform isopropanol unknown solvate http://dx.doi.org/10.1002/chem.201201701 Chem.-Eur.J. E.W.Y.Wong; A.Miura; M.D.Wright; Qi He; C.J.Walsby; S.Shimizu; N.Kobayashi; D.B.Leznoff
XIVDUE Dark Blue C56 H52 Au1 N4 O12,2(C2 H3 N1) [5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl)porphyrinato]-gold(ii) acetonitrile solvate Not informed CSD Communication(Private Communication) Guiyu Liu
ROBVOW Brown C44 H28 Au1 N4 1+,C38 H8 F15 N4 Ni1 O1 1-,0.682(C8 H18) (5,10,15,20-tetraphenylporphyrinato)-gold (5-oxido-10,15,20-tris(pentafluorophenyl)porphyrinato)-nickel octane solvate http://dx.doi.org/10.1016/j.isci.2019.03.027 iScience Y.Haketa; Yuya Bando; Y.Sasano; H.Tanaka; N.Yasuda; I.Hisaki; H.Maeda
TEHZOY Brown C44 H28 Au1 N4 (5,10,15,20-tetraphenylporphyrinato)-gold(ii) http://dx.doi.org/10.1038/nchem.2836 Nature Chemistry S.Prei; C.Forster; Sven Otto; M.Bauer; P.Muller; D.Hinderberger; H.H.Haeri; L.Carrella; K.Heinze
ILIWIJ Black C44 H28 Au1 N4 1+,Cl1 O4 1- (5,10,15,20-Tetraphenylporphyrinato)-gold(iii) perchlorate http://dx.doi.org/10.1039/b303294a Chem.Commun. Chi-Ming Che; R.Wai-Yin Sun; Wing-Yiu Yu; Chi-Bun Ko; Nianyong Zhu; Hongzhe Sun
I have no idea if the Au center bound to a porphyrin can still bind oxygen, like iron bound to heme does in hemoglobin, probably not. But one of the compounds, the green one (HAZMON) has a chloride bound to Au. So I wildly speculate a similar structure could be useful to some organism with a exotic biochemistry, that somehow breathes chlorine instead of oxygen.
As other people noticed, Earth crust is very poor in Au, as most of it sank together with iron and other siderophiles to the planet core as it formed. Lifeforms would have a hard time gathering the element, unless a planet somehow avoided to end with most of it trapped in the core. Cyanide is very poisonous to most earth life, but reacts with gold, so I imagine a environment rich in this compound could help mobilize the metal and make it available to any organisms with a biochemistry able to survive and thrive in its presence. I believe here on Earth the less abundant element to have important biological functions is iodine. Related:Abundances of the elements and Abundance of elements in Earth's crust.