( ( Proteins ( made ( of ( ( ( two or ) more ) ( polypeptide chains ) ) ) ) ) ( ( have ( quaternary structure ) ) . ) )
(ROOT (S (NP (NP (NNPS Proteins)) (VP (VBN made) (PP (IN of) (NP (QP (CD two) (CC or) (JJR more)) (JJ polypeptide) (NNS chains))))) (VP (VBP have) (NP (JJ quaternary) (NN structure))) (. .)))
Proteins made of two or more polypeptide chains have quaternary structure.
(ROOT (S (NP (NNP Insulin)) (VP (VBZ is) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (CD two) (JJ polypeptide) (NNS chains))))) (. .)))