Identification and Functional Characterization of a Novel Acetylcholine-binding Protein from the Marine Annelid Capitella teleta
We identified a homologue of the molluscan acetylcholine-binding protein (AChBP) in the marine polychaete Capitella teleta, from the annelid phylum. The amino acid sequence of C. teleta AChBP (ct-AChBP) is 21-30% identical with those of known molluscan AChBPs. Sequence alignments indicate that ct-AChBP has a shortened Cys loop compared to other Cys loop receptors, and a variation on a conserved Cys loop triad, which is associated with ligand binding in other AChBPs and nicotinic ACh receptor (nAChR) {alpha} subunits. Within the D loop of ct-AChBP, a conserved aromatic residue (Tyr or Trp) in nAChRs and molluscan AChBPs, which has been implicated directly in ligand binding, is substituted with an isoleucine. Mass spectrometry results indicate that Asn122 and Asn216 of ct-AChBP are glycosylated when expressed using HEK293 cells. Small-angle X-ray scattering data suggest that the overall shape of ct-AChBP in the apo or unliganded state is similar to that of homologues with known pentameric crystal structures. NMR experiments show that acetylcholine, nicotine, and {alpha}-bungarotoxin bind to ct-AChBP with high affinity, with KD values of 28.7 {micro}M, 209 nM, and 110 nM, respectively. Choline bound with a lower affinity (K{sub D} = 163 {micro}M). Our finding of a functional AChBP in a marine annelid demonstrates that AChBPs may exhibit variations in hallmark motifs such as ligand-binding residues and Cys loop length and shows conclusively that this neurotransmitter binding protein is not limited to the phylum Mollusca.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1019853
- Report Number(s):
- BNL--95699-2011-JA
- Journal Information:
- Biochemistry, Journal Name: Biochemistry Journal Issue: 10 Vol. 49; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
Similar Records
Atomic interactions of neonicotinoid agonists with AChBP: Molecular recognition of the distinctive electronegative pharmacophore
Competitive docking model for prediction of the human nicotinic acetylcholine receptor α7 binding of tobacco constituents
Molecular-Dynamics Simulations of ELIC a Prokaryotic Homologue of the Nicotinic Acetylcholine Receptor
Journal Article
·
Mon Jul 28 04:00:00 UTC 2008
· Proc. Natl. Acad. Sci. USA
·
OSTI ID:1006671
Competitive docking model for prediction of the human nicotinic acetylcholine receptor α7 binding of tobacco constituents
Journal Article
·
Thu Feb 08 00:00:00 UTC 2018
· Oncotarget
·
OSTI ID:1630013
Molecular-Dynamics Simulations of ELIC a Prokaryotic Homologue of the Nicotinic Acetylcholine Receptor
Journal Article
·
Thu Jan 01 04:00:00 UTC 2009
· Biophysical Journal
·
OSTI ID:981808