( ( Features ( of titin ) ) ( ( had ( suggested ( that ( ( ( calcium and ) ( a ( small ( well-known ( regulator protein ) ) ) ) ) ( called ( calmodulin ( were ( involved ( in ( these ( structural changes ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Features)) (PP (IN of) (NP (NN titin)))) (VP (VBD had) (VP (VBN suggested) (SBAR (IN that) (S (NP (NP (NN calcium)) (CC and) (NP (DT a) (JJ small) (JJ well-known) (NN regulator) (NN protein))) (VP (VBD called) (SBAR (S (NP (NN calmodulin)) (VP (VBD were) (VP (VBN involved) (PP (IN in) (NP (DT these) (JJ structural) (NNS changes)))))))))))) (. .)))
Features of titin had suggested that calcium and a small well-known regulator protein called calmodulin were involved in these structural changes.
(ROOT (S (NP (DT The) (ADJP (JJS largest) (VBN known)) (NNS proteins)) (VP (VBP are) (ADJP (JJ titins))) (. .)))