title: Molecular characterization of an acetylcholinesterase from the hemichordate Saccoglossus kowalevskii.
abstract: Our goal is to understand the evolution of the structure and function of cholinesterases (ChEs) in the deuterostome lineage and in particular to understand the role of paralogous enzymes such as the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of the vertebrates. We have, in the past, characterized ChEs in two acraniate deuterostomes: amphioxus (a cephalochordate) and Ciona intestinalis (a urochordate). Here we present results on an AChE from a basal deuterostome, a model hemichordate, the acorn worm Saccoglossus kowalevskii. Of the eight genes coding for putative ChE-like proteins possessing Trp84, a characteristic of the choline-binding catalytic subsite of ChEs, we cloned a full length cDNA with a coding sequence typical of an acraniate AChE possessing a C-terminal exon coding for a typical T-peptide. We then used in vitro expression of the cDNA in COS-7 cells to characterize the AChE kinetically, pharmacologically, and biochemically. The cDNA codes for an AChE (AChE1), which is found in monomeric (G1), dimeric (G2), and tetrameric (G4) forms; and interacts with poly-L-proline, PRiMA, and ColQ, characteristic of an AChE possessing a T-peptide. The expression of the AChE is temperature dependent, with greater expression at 30 °C. We discuss the implications of these data for the evolution of the ChEs in the deuterostomes.
authors.affiliation: Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, USA. Electronic address: lpezzeme@bsc.edu.
authors.forename: Leo
authors.initials: L
authors.lastname: Pezzementi
authors.affiliation: Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, USA.
authors.forename: Cybil
authors.initials: C
authors.lastname: Geiss
authors.affiliation: Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, USA.
authors.forename: William
authors.initials: W
authors.lastname: King
authors.affiliation: INRA Dynamique Musculaire et Métabolisme, 34000 Montpellier, France; Université de Montpellier, 34000 Montpellier, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lenfant
authors.affiliation: INRA Dynamique Musculaire et Métabolisme, 34000 Montpellier, France; Université de Montpellier, 34000 Montpellier, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chatonnet
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D000845:Annelida / Q000145:classification / Q000201:enzymology* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D055503:Protein Multimerization; D013696:Temperature
chemical_list: D000110:Acetylcholinesterase
keywords: Acetylcholinesterase; Butyrylcholinesterase; Evolution; Saccoglossus kowalevskii