( double ( ( helix ( ( The ( normal ( structural configuration ) ) ) ( of ( ( DNA consisting ) ( of ( ( two helices ) ( winding ( about ( the ( same axis ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (VB double)) (VP (VBZ helix) (NP (NP (DT The) (JJ normal) (JJ structural) (NN configuration)) (PP (IN of) (NP (NP (NNP DNA) (NNP consisting)) (PP (IN of) (NP (NP (CD two) (NNS helices)) (VP (VBG winding) (PP (IN about) (NP (DT the) (JJ same) (NNS axis)))))))))) (. .)))
double helix The normal structural configuration of DNA consisting of two helices winding about the same axis.
(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)))))) (. .)))