( ( ( The ( basic structure ) ) ( of ( a protein ) ) ) ( ( is ( ( a ( string-like molecule ) ) ( which ( is ( constructed ( from ( units ( called ( amino acids ) ) ) ) ) ) ) ) ) ; ) )
(ROOT (S (NP (NP (DT The) (JJ basic) (NN structure)) (PP (IN of) (NP (DT a) (NN protein)))) (VP (VBZ is) (NP (NP (DT a) (JJ string-like) (NN molecule)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBN constructed) (PP (IN from) (NP (NP (NNS units)) (VP (VBN called) (NP (JJ amino) (NNS acids))))))))))) (: ;)))
The basic structure of a protein is a string-like molecule which is constructed from units called amino acids;
(ROOT (S (NP (DT A) (NN protein)) (VP (VBZ is) (NP (NP (DT an) (JJ organic) (NN compound)) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (NP (JJ small) (NNS molecules)) (VP (VBN called) (NP (JJ amino) (NNS acids)))))))) (. .)))