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PR00356

Identifier
ANTIFREEZEII  [View Relations]  [View Alignment]  
Accession
PR00356
No. of Motifs
7
Creation Date
11-MAY-1995  (UPDATE 06-JUN-1999)
Title
Type II antifreeze protein signature
Database References

PROSITE; PS00615 C_TYPE_LECTIN
INTERPRO; IPR002353
Literature References
1. SONNICHSEN, F.D., SYKES, B.D. AND DAVIES, P.L.
Comparative modelling of the three-dimensional structure of Type II
antifreeze protein.
PROTEIN SCI. 4 460-471 (1995).

Documentation
Marine teleosts from polar oceans can be protected from freezing in icy
sea-water by serum antifreeze proteins (AFPs) or glycoproteins (AFGPs) [1]:
these function by binding to, and preventing the growth of, ice crystals
within the fish. Despite functional similarity, the proteins are
structurally diverse and include glycosylated and at least 3 non-
glycosylated forms: the AFGP of nototheniids and cods are polymers of a
tripeptide repeat, Ala-Ala-Thr, with a disaccharide attached to the
threonine residue; type I AFPs are Ala-rich, alpha-helical peptides
found in flounder and sculpin; type II AFPs of sea-raven, smelt and
herring are Cys-rich proteins; and type III AFPs, found in eel pouts,
are rich in beta-structure.
 
Although no direct structural information is available for type II AFPs,
their sequences are similar to the carbohydrate recognition domain (CRD)
of Ca2+-dependent lectins. This domain is present in a superfamily of
proteins that bind sugars specifically through contact with a calcium
ion. The extent of similarity within the superfamily is confined to 
short motifs and single amino acids at intervals throughout the protein. 
 
ANTIFREEZEII is a 7-element fingerprint that provides a signature for
type II antifreeze proteins. The fingerprint was derived from an initial
alignment of 2 sequences: the motifs were drawn from conserved regions
spanning the full alignment length - motifs 6 and 7 span the region
encoded by PROSITE pattern C_TYPE_LECTIN (PS00615), which includes 3
conserved cysteine residues in the C-terminal portion of the CRD. Two
iterations on OWL26.0 were required to reach convergence, at which point
a true set comprising 4 sequences was identified. Numerous partial matches
were also found, all of which belong to the C-type lectin superfamily.
 
An update on SPTR37_9f identified a true set of 3 sequences.
Summary Information
3 codes involving  7 elements
0 codes involving 6 elements
0 codes involving 5 elements
0 codes involving 4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
73333333
60000000
50000000
40000000
30000000
20000000
1234567
True Positives
ANP_HEMAM     ANP_OSMMO     Q91992        
Sequence Titles
ANP_HEMAM   ANTIFREEZE PROTEIN PRECURSOR (AFP) - HEMITRIPTERUS AMERICANUS (SEA RAVEN). 
ANP_OSMMO ANTIFREEZE PROTEIN PRECURSOR (AFP) - OSMERUS MORDAX (RAINBOW SMELT).
Q91992 ANTIFREEZE PROTEIN TYPE II - CLUPEA HARENGUS (ATLANTIC HERRING).
Scan History
OWL26_0    2  50   NSINGLE    
SPTR37_9f 2 4 NSINGLE
Initial Motifs
Motif 1  width=13
Element Seqn Id St Int Rpt
ECPTDWKMFNGRC ANP_OSMMO 37 37 -
NCPAGWQPLGDRC ANP_HEMAM 40 40 -

Motif 2 width=18
Element Seqn Id St Int Rpt
CFLFNPLQLHWAHAQISC ANP_OSMMO 49 -1 -
CIYYETTAMTWALAETNC ANP_HEMAM 52 -1 -

Motif 3 width=18
Element Seqn Id St Int Rpt
MKDGANLASIHSLEEYAF ANP_OSMMO 67 0 -
MKLGGHLASIHSQEEHSF ANP_HEMAM 70 0 -

Motif 4 width=17
Element Seqn Id St Int Rpt
WIGGSDCHVSTYWFWMD ANP_OSMMO 97 12 -
WIGGSACLQAGAWTWSD ANP_HEMAM 97 9 -

Motif 5 width=12
Element Seqn Id St Int Rpt
FTDWCAAQPDFT ANP_OSMMO 119 5 -
FRSWCSTKPDDV ANP_HEMAM 119 5 -

Motif 6 width=12
Element Seqn Id St Int Rpt
LTECCIQINVGV ANP_OSMMO 131 0 -
LAACCMQMTAAA ANP_HEMAM 131 0 -

Motif 7 width=14
Element Seqn Id St Int Rpt
WNDTPCTHLHASVC ANP_OSMMO 146 3 -
WDDLPCPASHKSVC ANP_HEMAM 146 3 -
Final Motifs
Motif 1  width=13
Element Seqn Id St Int Rpt
ECPTDWKMFNGRC ANP_OSMMO 37 37 -
ECPTDWKMFNGRC Q91992 20 20 -
NCPAGWQPLGDRC ANP_HEMAM 40 40 -

Motif 2 width=18
Element Seqn Id St Int Rpt
CFLFNPLQLHWAHAQISC ANP_OSMMO 49 -1 -
CFLFNPLQLHWADAQESC Q91992 32 -1 -
CIYYETTAMTWALAETNC ANP_HEMAM 52 -1 -

Motif 3 width=18
Element Seqn Id St Int Rpt
MKDGANLASIHSLEEYAF ANP_OSMMO 67 0 -
MKEGANLASIHSLEESTF Q91992 50 0 -
MKLGGHLASIHSQEEHSF ANP_HEMAM 70 0 -

Motif 4 width=17
Element Seqn Id St Int Rpt
WIGGSDCHVSTYWFWMD ANP_OSMMO 97 12 -
WIGGTDCQVSTRWFWMD Q91992 80 12 -
WIGGSACLQAGAWTWSD ANP_HEMAM 97 9 -

Motif 5 width=12
Element Seqn Id St Int Rpt
FTDWCAAQPDFT ANP_OSMMO 119 5 -
YADWCAAQPDTT Q91992 102 5 -
FRSWCSTKPDDV ANP_HEMAM 119 5 -

Motif 6 width=12
Element Seqn Id St Int Rpt
LTECCIQINVGV ANP_OSMMO 131 0 -
LTECCIQMNVGI Q91992 114 0 -
LAACCMQMTAAA ANP_HEMAM 131 0 -

Motif 7 width=14
Element Seqn Id St Int Rpt
WNDTPCTHLHASVC ANP_OSMMO 146 3 -
WNDTPCTHLHSSIC Q91992 129 3 -
WDDLPCPASHKSVC ANP_HEMAM 146 3 -