b) C. Bonfio, L. Valer, S. Scintilla, S. Shah, D. J. Evans, L. Jin, J. W. Szostak, D. D. Sasselov, J. D. Sutherland and S. S. Mansy, Nat. Chem., 2017, 9, 1229–1234 CrossRef CAS PubMed; Full size image Phylogenetic analysis of the CT domains: The urea carboxylase carboxyl transferase (UCT) c) M. P. Robertson and G. F. Joyce, Cold Spring Harbor Perspect. Biol., 2012, 4, a003608 Search PubMed; c) D. R. Nelson, T. Kamataki, D. J. Waxman, F. P. Guengerich, R. W. Estabrook, R. Feyereisen, F. J. Gonzalez, M. J. Coon, I. C. Gunsalus, O. Gotoh, K. Okuda and D. W. Nebert, DNA Cell Biol., 1993, 12, 1–51 CrossRef CAS PubMed. In the context of Fe- and S-containing metalloclusters, it is sensible to include hydrogenases in the discussion.

Leon-Del-Rio A, Gravel RA: Sequence requirements for the biotinylation of carboxyl-terminal fragments of human propionyl-CoA carboxylase alpha subunit expressed in Escherichia coli. J Biol Chem. 1994, 269: 22964-22968. a) S. Joshi, D. Fedoseyenko, N. Mahanta, H. Manion, S. Naseem, T. Dairi and T. P. Begley, Curr. Opin. Chem. Biol., 2018, 47, 134–141 CrossRef CAS PubMed; Once iron–sulfur clusters were available they could have rearranged themselves to form the different clusters that are now found in (Fe–S) proteins. These also include more complex metal clusters in which iron is exchanged for other metals. As a consequence, this evolution led to enzyme classes such as nitrogenases and hydrogenases, both key enzymes in the evolution of life. Here, based on the concept of determining the coenzymes required for their biosynthetic generation, an evolutionary relationship can be proposed ( Scheme 5). Noteworthy, four of the five clusters mentioned (the [FeFe], [MoFe], and [VFe] cofactors in nitrogenases and the [FeFe] ‘H-cluster’ found in the corresponding hydrogenase) alone had to wait for SAM 17 to appear ( Scheme 4) before they could step onto the stage.A. Marquet, B. Tse Sum Bui, A. G. Smith and M. J. Warren, Nat. Prod. Rep., 2007, 24, 1027–1040 RSC. ONE PER DAY: One easy-to-swallow tablet a day will give you all the benefits of our maximum strength Biotin supplement. a) G. Gutzke, B. Fischer, R. R. Mendel and G. Schwarz, J. Chem. Biol., 2001, 276, 36268–36274 CrossRef CAS PubMed;

a) M. Zhang, L. Wang and D. Zhong, Arch. Biochem. Biophys., 2017, 632, 158–174 CrossRef CAS PubMed; d) Y. Mathur, S. Sreyas, P. M. Datar, M. B. Sathian and A. B. Hazra, J. Biol. Chem., 2020, 295, 10522–10534 CrossRef CAS PubMed. Bramwell H, Hunter IS, Coggins JR, Nimmo HG: Propionyl-CoA carboxylase from Streptomyces coelicolor A3(2): cloning of the gene encoding the biotin-containing subunit. Microbiology. 1996, 142: 649-655. 10.1099/13500872-142-3-649. Pyruvate carboxylases (PYC; E.C. 6.4.1.1) catalyze the carboxylation of pyruvate to oxaloacetate, an important function for anaplerosis, gluconeogenesis and fatty acid synthesis. A significant feature concerning the protein domain composition of PYC is the homology of the BC and BCCP domains with those of the rest of biotin-dependent carboxylases, in contrast with the independent origin of the CT element. Most bacteria and eukaryotes bear a polypeptidic PYC carrying the BC domain in its N-terminal end, the CT in the central part and the BCCP domain in the C-terminus [ 35]. Recent studies have discovered a domain situated between the BC and CT domains and between the CT and BCCP domains in Rhizobium etli [ 36– 38]. The new domain, referred to as the PYC tetramerization (PT) or allosteric domain, would play a role in tetramerization of PYC subunits and allosteric regulation of PYC by acetyl-CoA. Finally, archaea and some bacteria contain an acetyl-CoA-independent PYC with two different subunits instead of one polypeptide: the BC α-subunit and the CT/BCCP β-subunit [ 39– 42].b) A. Chatterjee, A. B. Hazra, S. Abdelwahed, D. G. Hilmey and T. P. Begley, Angew. Chem., Int. Ed., 2010, 49, 8653–8656 CrossRef CAS PubMed. A strong point of this scenario is its relative simplicity, relying on the general assumption of aggregative peptide domain architecture as a major force in protein evolution [ 63]. Noteworthy, this hypothesis assumes the independent emergence of the PT (ancient PYC) domain and the BT (bacterial XCC) domain. Thus, a convergent evolution has to be invoked to explain BT and PT structural resemblances. Despite that little is known concerning the characteristics and conservation of the BT/PT domains, their shared structure consisting of a conserved helix and several β-strands seems simple enough to hypothesize that it could have emerged twice independently and their conserved position between the BC and the BCCP domains could be the result of structural constraints related to their common subunit-interaction roles. b) P. N. Evans, J. A. Boyd, A. O. Leu, B. J. Woodcroft, D. H. Parks, P. Hugenholtz and G. W. Tyson, Nat. Rev. Microbiol., 2019, 17, 219–232 CrossRef CAS PubMed. d) M. J. Rudolph, M. M. Wuebbens, K. V. Rajagopalan and H. Schindelin, Nat. Struct. Biol., 2001, 8, 42–46 CrossRef CAS PubMed.

b) H. D. Heilmann and F. Lingens, Hoppe-Seyler's Z. Physiol. Chem., 1968, 349, 231–236 CrossRef CAS. J. J. Braymera, S. A. Freiberta, M. Rakwalska-Bangea and R. Lilla, Biochim. Biophys. Acta, Mol. Cell Res., 2021, 1868, 118863 CrossRef. Huang CS, Sadre-Bazzaz K, Shen Y, Deng B, Zhou ZH, Tong L: Crystal structure of the alpha(6)beta(6) holoenzyme of propionyl-coenzyme A carboxylase. Nature. 2010, 466: 1001-1005. 10.1038/nature09302. Chemically, the methanogenic coenzyme THMPT 24 and THF 16 behave similarly, as both are carbon carriers. Methanopterin is also capable of uploading oxidation states between formyl and methyl, but there are differences between the two pterin-based coenzymes. As such ATP is consumed in the entry of carbon from CO 2 into the 5,6,7,8-tetrahydrofolate pathway, which is not the case for tetrahydromethanopterin. Pirner HM, Stolz J: Biotin sensing in Saccharomyces cerevisiae is mediated by a conserved DNA element and requires the activity of biotin-protein ligase. J Biol Chem. 2006, 281: 12381-12389. 10.1074/jbc.M511075200.

Why add Coconut Oil to Biotin?

M. R. Challand, F. T. Martins and P. L. Roach, J. Biol. Chem., 2010, 285, 5240–5248 CrossRef CAS PubMed. a) H. A. Dailey, T. A. Dailey, S. Gerdes, D. Jahn, M. Jahn, M. R. O'Brian and M. J. Warren, Microbiol. Mol. Biol. Rev., 2017, 81, e00048-16 CrossRef PubMed; The biosynthesis of the Fe(CN) 2CO complex occurs in a protein cluster composed of HypC, HypD, and HypE. Here, cyanide originates from enzyme-bound thiocarbamoylate and requires ATP for activation before cyanide is transferred to iron. Interestingly, enzyme-bound carbamothioate has been proposed as intermediate. Menendez C, Bauer Z, Huber H, Gad'on N, Stetter KO, Fuchs G: Presence of acetyl coenzyme A (CoA) carboxylase and propionyl-CoA carboxylase in autotrophic Crenarchaeota and indication for operation of a 3-hydroxypropionate cycle in autotrophic carbon fixation. J Bacteriol. 1999, 181: 1088-1098. Reche PA: Lipoylating and biotinylating enzymes contain a homologous catalytic module. Protein Sci. 2000, 9: 1922-1929. 10.1110/ps.9.10.1922.

An alternative origin of archaeal biotin carboxylases through ancient HGTs from bacteria cannot be completely excluded. However, except for some particular cases limited to some specific organisms, the distribution and the phylogenetic trees of the BC and the PCT domains are congruent with the expected phylogeny of Archaea. As a result, the hypothetical HGT events responsible for the presence of the BC and PCT domains in Archaea should have been ancient enough to predate the last common archaeal ancestor, and thus HGT cannot be favored over the simple vertical inheritance from the cenancestor. Concerning the CCT domain, some groups, as for example the Halobacteriales, may have inherited their sequences by HGT from bacterial donors, but our results do not provide enough support neither to the monophyly of all archaeal CCTs nor to the putative HGT-mediated origin of these sequences, so this issue remains open.Comparing FMN/FAD biosynthesis with that of prFMN 36, it is evident that the latter must be an evolutionary downstream metabolite that appeared on the scene only after riboflavin-based coenzyme biosynthesis was established. Gago G, Kurth D, Diacovich L, Tsai SC, Gramajo H: Biochemical and structural characterization of an essential acyl coenzyme A carboxylase from Mycobacterium tuberculosis. J Bacteriol. 2006, 188: 477-486. 10.1128/JB.188.2.477-486.2006. Recent systems chemistry approaches have argued that the basic metabolic networks of life, 106,107 such as the TCA cycle and especially its reverse counterpart, the rTCA cycle, but also others, existed long before the appearance of LUCA. 108–110 These networks arose in parallel with RNA, which receives special attention in the RNA-world theory because of its catalytic and self-replicating capabilities. 101