( ( ( The ( Watson-Crick model ) ) ( -LRB- ( 6 -RRB- ) ) ) ( ( postulates ( ( two ( right-handed ( helical ( nucleotide chains ) ) ) ) ( ( coiled ( around ( the ( same axis ) ) ) ) ( to ( form ( a ( double helix ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNP Watson-Crick) (NN model)) (PRN (-LRB- -LRB-) (NP (CD 6)) (-RRB- -RRB-))) (VP (VBZ postulates) (NP (NP (CD two) (JJ right-handed) (JJ helical) (NN nucleotide) (NNS chains)) (VP (VBN coiled) (PP (IN around) (NP (DT the) (JJ same) (NNS axis))) (S (VP (TO to) (VP (VB form) (NP (DT a) (JJ double) (NN helix)))))))) (. .)))
The Watson-Crick model (6) postulates two right-handed helical nucleotide chains coiled around the same axis to form a double helix.
(ROOT (S (NP (DT The) (JJ double) (NN helix) (NN dna) (NN shape)) (VP (VBZ forms) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (CD two) (JJ nucleotide) (NNS chains)) (VP (VB wrap) (PRT (RP around)) (NP (DT the) (JJ same) (NNS axis)))))) (. .)))