1w27

Publication Abstract from PubMed

Because of its key role in secondary phenylpropanoid metabolism, Phe ammonia-lyase is one of the most extensively studied plant enzymes. To provide a basis for detailed structure-function studies, the enzyme from parsley (Petroselinum crispum) was crystallized, and the structure was elucidated at 1.7-A resolution. It contains the unusual electrophilic 4-methylidene-imidazole-5-one group, which is derived from a tripeptide segment in two autocatalytic dehydration reactions. The enzyme resembles His ammonia-lyase from the general His degradation pathway but contains 207 additional residues, mainly in an N-terminal extension rigidifying a domain interface and in an inserted alpha-helical domain restricting the access to the active center. Presumably, Phe ammonia-lyase developed from His ammonia-lyase when fungi and plants diverged from the other kingdoms. A pathway of the catalyzed reaction is proposed in agreement with established biochemical data. The inactivation of the enzyme by a nucleophile is described in detail.

Structural basis for the entrance into the phenylpropanoid metabolism catalyzed by phenylalanine ammonia-lyase.,Ritter H, Schulz GE Plant Cell. 2004 Dec;16(12):3426-36. Epub 2004 Nov 17. PMID:15548745^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.