Corrin

{{Other uses|Corrin (disambiguation)}} {{Chembox | verifiedrevid = 443543138 | ImageFile = Corrin.svg | ImageSize = 220px | IUPACName = (5''Z'',9''Z'',14''Z'')-2,3,7,8,12,13,17,18,19,22-Decahydro-1''H''-corrin<ref>https://pubchem.ncbi.nlm.nih.gov/compound/6438343#section=IUPAC-Name&fullscreen=true</ref> | OtherNames = | Section1 = {{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 16736705 | InChIKey = WUPRCGRRQUZFAB-DEGKJRJSBL | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C19H22N4/c1-3-14-10-16-5-7-18(22-16)19-8-6-17(23-19)11-15-4-2-13(21-15)9-12(1)20-14/h9-11,18-19,22H,1-8H2/b12-9-,15-11-,16-10- | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = WUPRCGRRQUZFAB-DEGKJRJSSA-N | CASNo_Ref = {{cascite|correct|??}} | CASNo=262-76-0 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 288E04GRMT | PubChem=6438343 | InChI = 1/C19H22N4/c1-3-14-10-16-5-7-18(22-16)19-8-6-17(23-19)11-15-4-2-13(21-15)9-12(1)20-14/h9-11,18-19,22H,1-8H2/b12-9-,15-11-,16-10- | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 33221 | SMILES = N=1C=4CCC=1\C=C2/NC(CC2)C\5CC/C(C=C3\CC/C(=N3)/C=4)=N/5 }} | Section2 = {{Chembox Properties | Formula=C₁₉H₂₂N₄ | MolarMass=306.40478 | Appearance= | Density= | MeltingPt= | BoilingPt= | Solubility= }} | Section3 = {{Chembox Hazards | MainHazards= | FlashPt= | AutoignitionPt = }} }} '''Corrin''' is a heterocyclic compound. Although not known to exist on its own, the molecule is of interest as the parent macrocycle related to the cofactor and chromophore in vitamin B₁₂. Its name reflects that it is the "core" of vitamin B₁₂ (cobalamins). Compounds with a corrin core are known as "corrins".<ref>Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. {{ISBN|1-57259-153-6}}.</ref>

There are two chiral centres, which in natural compounds like cobalamin have the same stereochemistry.

==Coordination chemistry== {{main|vitamin B12|l1=Vitamin B₁₂}} Upon deprotonation, the corrinoid ring is capable of binding cobalt. In vitamin B₁₂, the resulting complex also features a benzimidazole-derived ligand, and the sixth site on the octahedron serves as the catalytic center.

The corrin ring resembles the porphyrin ring.<ref>{{cite journal |doi=10.1021/cr030720z|title=Chemistry and Enzymology of Vitamin B12 |year=2005 |last1=Brown |first1=Kenneth L. |journal=Chemical Reviews |volume=105 |issue=6 |pages=2075–2150 |pmid=15941210 }}</ref> Both feature four pyrrole-like subunits organized into rings. Corrins have a central 15-membered {{chem2|C11N4}} ring whereas porphyrins have an interior 16-membered {{chem2|C12N4}} ring. All four nitrogen centers are linked by conjugation structure, with alternating double and single bonds. In contrast to porphyrins, corrins lack one of the carbon groups that link the pyrrole-like units into a fully conjugated structure. With a conjugated system that extends only 3/4 of the way around the ring, and does not include any of the outer edge carbons, corrins have a number of non-conjugated sp³ carbons, making them more flexible than porphyrins and not as flat. A third closely related biological structure, the chlorin ring system found in chlorophyll, is intermediate between porphyrin and corrin, having 20 carbons like the porphyrins and a conjugated structure extending all the way around the central atom, but with only 6 of the 8 edge carbons participating. Corroles (octadehydrocorrins) are fully aromatic derivatives of corrins.

==References== {{reflist}}

== Further reading == * {{cite journal |last1=Kieninger |first1=Christoph |last2=Deery |first2=Evelyne |last3=Lawrence |first3=Andrew D. |last4=Podewitz |first4=Maren |last5=Wurst |first5=Klaus |last6=Nemoto‐Smith |first6=Emi |last7=Widner |first7=Florian J. |last8=Baker |first8=Joseph A. |last9=Jockusch |first9=Steffen |last10=Kreutz |first10=Christoph R. |last11=Liedl |first11=Klaus R. |last12=Gruber |first12=Karl |last13=Warren |first13=Martin J. |last14=Kräutler |first14=Bernhard |title=The Hydrogenobyric Acid Structure Reveals the Corrin Ligand as an Entatic State Module Empowering B 12 Cofactors for Catalysis |journal=Angewandte Chemie International Edition |date=29 July 2019 |volume=58 |issue=31 |pages=10756–10760 |doi=10.1002/anie.201904713|pmid=31115943 |pmc=6771967 }}

{{Tetrapyrroles}}

Category:Biomolecules Category:Tetrapyrroles Category:Metabolism Category:Macrocycles Category:Schiff bases