( ( ( The ( innermost ( protein layer ) ) ) ( -LRB- ( ( viral core ) -RRB- ) ) ) ( ( is ( formed ( by ( VP2 molecules ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ innermost) (NN protein) (NN layer)) (PRN (-LRB- -LRB-) (NP (JJ viral) (NN core)) (-RRB- -RRB-))) (VP (VBZ is) (VP (VBN formed) (PP (IN by) (NP (CD VP2) (NNS molecules))))) (. .)))
The innermost protein layer (viral core) is formed by VP2 molecules.
(ROOT (S (NP (NP (DT The) (JJ innermost) (NN layer)) (PP (IN of) (NP (DT the) (NN sun)))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (DT the) (NN core))))) (. .)))