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PR00879

Identifier
ACHEFISH  [View Relations]  [View Alignment]  
Accession
PR00879
No. of Motifs
4
Creation Date
06-JUL-1998  (UPDATE 06-JUN-1999)
Title
Fish acetylcholinesterase signature
Database References
PRINTS; PR00878 CHOLNESTRASE
INTERPRO; IPR000908
PDB; 2ACE
SCOP; 2ACE
CATH; 2ACE
Literature References
1. VOET, D. AND VOET, J.G.
Biochemical communications: Hormones and neurotransmission.
BIOCHEMISTRY 34(4) 1298-1299 (1995).
 
2. COUSIN, X., HOTELIER, T., GILES, K., TOUTANT, J.P. AND CHATONNET, A.
aCHEdb: the database system for ESTHER, the a/b fold family of proteins and
the cholinesterase gene server.
NUCLEIC ACIDS RES. 26 226-228 (1998).
 
3. THE ESTHER DATABASE
http://meleze.ensam.inra.fr/cholinesterase/definitions.html
 
4. CHOLINESTERASES
http://bnlstb.bio.bnl.gov:8000/disk$3/giles/che.html

Documentation
Acetylcholine is involved in the transfer of messages across a variety of
synapses in vertebrates and invertebrates. The diverse physiological effects
attributable to this molecule arise from the presence of specific receptors
in the postsynaptic cell membranes. Several classes of receptor are known, 
most of which translate the binding of acetylcholine into the opening of 
channels for the passage of ions, such as sodium and potassium.
 
Acetylcholinesterase is an enzyme that catalyses the hydrolysis of 
acetylcholine to choline and acetate:
 
     Acetylcholine + H(2)O -> Choline + Acetate 	     
 
The enzyme also acts on a variety of acetic esters and catalyses trans-
acetylations. It is found in, or attached to, cellular or basement membranes
of presynaptic cholinergic neurons and postsynaptic cholinoceptive cells.
To prevent continuous firing of nerve impulses, acetylcholinesterase has a
high K(cat) (~14000/s), to ensure that acetylcholine is broken down quickly.
 
Cholinesterases constitute a family of enzymes that fall into two main
types, depending on their substrate preference: enzymes that preferentially
hydrolyse acetyl esters are termed acetylcholinesterase (AChE) (EC 3.1.1.7); 
and those that prefer other types of ester, such as butyrylcholine are 
termed butyrylcholinesterase (BChE) (EC 3.1.1.8). 
 
The 3D structure of acetylcholinesterase from the electric ray has been
determined. The fold belongs to the alpha/beta class, with a 3-layer
alpha-beta-alpha sandwich architecture.
 
ACHEFISH is a 4-element fingerprint that provides a signature for fish
acetylcholinesterases. The fingerprint was derived from an initial alignment
of 4 sequences: the motifs were drawn from short conserved regions within
the central portion of the alignment - motif 1 spans the N-terminus of 
helix 12 and part of the preceding loop; motif 2 includes the N-terminal
end of helix 14 and part of its preceding loop; motif 3 encompasses the 
N-terminus of helix 18 and part of the preceding loop; and motif 4 encodes
most of helix 19. Two iterations on OWL30.2 were required to reach
convergence, at which point a true set comprising 6 sequences was identified.
 
An update on SPTR37_9f identified a true set of 3 sequences.
Summary Information
3 codes involving  4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
43333
30000
20000
1234
True Positives
ACES_BUNFA    ACES_TORCA    ACES_TORMA    
Sequence Titles
ACES_BUNFA  ACETYLCHOLINESTERASE PRECURSOR (EC 3.1.1.7) - BUNGARUS FASCIATUS (BANDED KRAIT). 
ACES_TORCA ACETYLCHOLINESTERASE PRECURSOR (EC 3.1.1.7) (ACHE) - TORPEDO CALIFORNICA (PACIFIC ELECTRIC RAY).
ACES_TORMA ACETYLCHOLINESTERASE PRECURSOR (EC 3.1.1.7) (ACHE) - TORPEDO MARMORATA (MARBLED ELECTRIC RAY).
Scan History
OWL30_2    2  150  NSINGLE    
SPTR37_9f 2 7 NSINGLE
Initial Motifs
Motif 1  width=6
Element Seqn Id St Int Rpt
EKKPQE ACES_TORCA 289 289 -
EKKPQE ACES_TORMA 292 292 -
ARPPQE ACES_MYXGL 167 167 -
SKNPQE ACES_BUNFA 299 299 -

Motif 2 width=9
Element Seqn Id St Int Rpt
EFFPTSLES ACES_TORMA 323 25 -
HFIIDSPIV ACES_MYXGL 198 25 -
EFFPTSLES ACES_TORCA 320 25 -
DFFPDTPEA ACES_BUNFA 330 25 -

Motif 3 width=9
Element Seqn Id St Int Rpt
AQNDALKNR ACES_MYXGL 279 72 -
DDNNGIKNR ACES_TORCA 401 72 -
DDNNGIKNR ACES_TORMA 404 72 -
DQDNREKNR ACES_BUNFA 411 72 -

Motif 4 width=9
Element Seqn Id St Int Rpt
HFVNKYTKF ACES_TORMA 430 17 -
QFANDYAKR ACES_BUNFA 437 17 -
HFVNKYTKF ACES_TORCA 427 17 -
EMATRYAEF ACES_MYXGL 305 17 -
Final Motifs
Motif 1  width=6
Element Seqn Id St Int Rpt
EKKPQE ACES_TORCA 289 289 -
EKKPQE ACES_TORMA 292 292 -
SKNPQE ACES_BUNFA 299 299 -

Motif 2 width=9
Element Seqn Id St Int Rpt
EFFPTSLES ACES_TORCA 320 25 -
EFFPTSLES ACES_TORMA 323 25 -
DFFPDTPEA ACES_BUNFA 330 25 -

Motif 3 width=9
Element Seqn Id St Int Rpt
DDNNGIKNR ACES_TORCA 401 72 -
DDNNGIKNR ACES_TORMA 404 72 -
DQDNREKNR ACES_BUNFA 411 72 -

Motif 4 width=9
Element Seqn Id St Int Rpt
HFVNKYTKF ACES_TORCA 427 17 -
HFVNKYTKF ACES_TORMA 430 17 -
QFANDYAKR ACES_BUNFA 437 17 -