Guanine
Guanine /É¡wa.nin/ is a nucleic base, more precisely a purine base (see also DNA and RNA). It is found in the form of a nucleotide: in DNA, it is dGMP for deoxyguanosine monophosphate or deoxyguanylate, and in RNA, it is GMP for guanosine monophosphate or guanylate. Guanine pairs with cytosine in both DNA and RNA and exists in six tautomeric forms, including four stereoisomers (1,9H, 1,7H, 3,9H, and 3,7H) and two tautomers with a different functional group (7,11H and 9,11H: oxo- and hydroxy-).
Accession Number : KLM0000210 This work is released into the public domain; please see our release statement.
Doug Markham has contributed a molecular mechanics computation of the structure! See below for the details.
Config Rule :
% guanine config(guanine,[ model(purine,[ diff(nit(1),nit(1,hyd)), diff(car(2,hyd),car(2,amine(10))), diff(car(6,hyd),car(6,oxy?))])]). config(purine,[ ring_system([ ring([ car(6,hyd)&, car(5)&, car(4)&, nit(3)&, car(2,hyd)&, nit(1)&]), ring([ nit(7)&, car(8,hyd)&, nit(9,hyd)&, car(4)&, car(5)&])], conjugate(1,pseudopos([car(4),car(5)]),2,pseudopos([car(4),car(5)]))])]).
Smiles String :
[c]1([nH][c]([c]2([c]([n]1)[nH][cH][n]2))[O-])[NH2] guanine
Terminal :
% guanine
c(2,12,(0,nonchiral))-[n(10,nil)~,n(3,flat)&,n(1,flat)&],
c(4,12,(0,nonchiral))-[n(3,flat)&,c(5,flat)&,n(9,flat)&],
c(5,12,(0,nonchiral))-[c(4,flat)&,c(6,flat)&,n(7,flat)&],
c(6,12,(0,nonchiral))-[o(1,nil)?,n(1,flat)&,c(5,flat)&],
c(8,12,(0,nonchiral))-[h(4,nil)~,n(7,flat)&,n(9,flat)&],
h(1,1,(0,nonchiral))-[n(10,nil)~],
h(2,1,(0,nonchiral))-[n(10,nil)~],
h(3,1,(0,nonchiral))-[n(1,nil)~],
h(4,1,(0,nonchiral))-[c(8,nil)~],
h(5,1,(0,nonchiral))-[n(9,nil)~],
n(1,14,(0,nonchiral))-[h(3,nil)~,c(2,flat)&,c(6,flat)&],
n(3,14,(0,nonchiral))-[c(2,flat)&,c(4,flat)&],
n(7,14,(0,nonchiral))-[c(5,flat)&,c(8,flat)&],
n(9,14,(0,nonchiral))-[h(5,nil)~,c(8,flat)&,c(4,flat)&],
n(10,14,(0,nonchiral))-[h(1,nil)~,h(2,nil)~,c(2,nil)~],
o(1,16,(0,nonchiral))-[c(6,nil)?]
The Terminals for all the Config Rules are in Prolog Definite Clause Grammar (DCG) form.They can be checked in the Manual here.
The compound's PDB file can be seen here.
Doug Markham of the Institute for Cancer Research, Fox Chase Cancer Center,Philadelphia, PA, has contributed the following structure for guanine. He computed this structure in sdf format using MacroModel, a molecular mechanics program. We have used Babel to convert the .sdf format to PDB format. You'll find it interesting to compare these structures to those computed using CONCORD.
Many thanks Doug!