This is the second AChE (not a cholinesterase see Frederick et al.)(the first introduced in ESTHER) It is farther related to vertebrates acche and is found only in adult cDNA library .It is not a contaminant as it is found in the genome ci0100131198. (Warning ci0100131198 is not properly conceptually spliced there is extra N-term unrelated sequence and some sequence is missing in C-term). The cioin-ACHE1 ( pointed to us by Leo Pezzementi) is found more often and is be the real AChE F7A0M2 F6Y1Y9 partial
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Eukaryota: NE > Opisthokonta: NE > Metazoa: NE > Eumetazoa: NE > Bilateria: NE > Deuterostomia: NE > Chordata: NE > Tunicata: NE > Ascidiacea: NE > Enterogona: NE > Phlebobranchia: NE > Cionidae: NE > Ciona: NE > Ciona intestinalis: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA KIVMMVQMRIALCVVFFINCAWSWESEPLAQEIAELLYSASSGVDFEFGN ARQFSEEFSTRQVLANPTADTTSGEFTGSSTEQVHAFYSVPYAKPPVGMF RFKPPVAAEHGGSINVSVPNYAQCSQSPQQCSDGTCGTTKTEDCLVLNIY APASVNLDSTNNMNELLPVMFWIHGGAFFAGSGTNPGYDGGWLSNKTNTV VVNINYRLDALGFLVFEEGDEKFDGNQGFKDQQLALKWVRDNIAKFGGDK NKVTIFGNSAGAQSVMLHVLSQESDPLFHRAIMQSNPAVFYYYTTDEAKV VTEELLDVLNCTTNKLDCLMNTEAHTLVNARAKVMAKAALRRNIFDGVEP YRPVTDGIEFIGQPLDQFQSGNWQKNKALIVGSNTEELEFINVVFRNRTV RKNSFEAVNNFVLGDYYGPIVSERYMQLAGERPGAQYDYTAILAQEIGDM FFVCPSRALARLASRSSPASDTVYLYSNSHPADLGACTSEASTCGHAYHG SEPRYVFNTVPNATADDMTVSDIFSDYWGSFAYTGYPQSDKYTAWPAYVP QSETIEGMSQWTNILLKAPNSETETGYKEDLCDFWDEIGFYVNITSPGDV TTLSTPVVSDVTEQAENEKTTVGSATMFGVTFNFTEKLMIAAGYFLFMMI NL
To learn more about the evolution of the cholinesterases (ChEs), acetylcholinesterase (AChE) and butyrylcholinesterase in the vertebrates, we investigated the AChE activity of a deuterostome invertebrate, the urochordate Ciona intestinalis, by expressing in vitro a synthetic recombinant cDNA for the enzyme in COS-7 cells. Evidence from kinetics, pharmacology, molecular biology, and molecular modeling confirms that the enzyme is AChE. Sequence analysis and molecular modeling also indicate that the cDNA codes for the AChE(T) subunit, which should be able to produce all three globular forms of AChE: monomers (G(1)), dimers (G(2)), and tetramers (G(4)), and assemble into asymmetric forms in association with the collagenic subunit collagen Q. Using velocity sedimentation on sucrose gradients, we found that all three of the globular forms are either expressed in cells or secreted into the medium. In cell extracts, amphiphilic monomers (G(1)(a)) and non-amphiphilic tetramers (G(4)(na)) are found. Amphiphilic dimers (G(2)(a)) and non-amphiphilic tetramers (G(4)(na)) are secreted into the medium. Co-expression of the catalytic subunit with Rattus norvegicus collagen Q produces the asymmetric A(12) form of the enzyme. Collagenase digestion of the A(12) AChE produces a lytic G(4) form. Notably, only globular forms are present in vivo. This is the first demonstration that an invertebrate AChE is capable of assembling into asymmetric forms. We also performed a phylogenetic analysis of the sequence. We discuss the relevance of our results with respect to the evolution of the ChEs in general, in deuterostome invertebrates, and in chordates including vertebrates.
The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis. The Ciona genome contains approximately 16,000 protein-coding genes, similar to the number in other invertebrates, but only half that found in vertebrates. Vertebrate gene families are typically found in simplified form in Ciona, suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development. The ascidian genome has also acquired a number of lineage-specific innovations, including a group of genes engaged in cellulose metabolism that are related to those in bacteria and fungi.
