| Literature References | 1. BARTA, E., DEAK, F. AND KISS, I.
Evolution of the hyaluronan-binding module of link protein.
BIOCHEM.J. 292 947-949 (1993).
2. KOHDA, D., MORTON, C.J., PARKAR, A.A., HATANAKA, H., INAGAKI, F.M.,
CAMPBELL, I.D. AND DAY A.J.
Solution structure of the link module: a hyaluronan-binding domain involved
in extracellular matrix stability and cell migration.
CELL 86 767-775 (1996).
3. BRISSET, N.C. AND PERKINS, S.J.
The protein fold of the hyaluronate-binding proteoglycan tandem repeat
domain of link protein, aggrecan and CD44 is similar to that of the C-type
lectin superfamily.
FEBS LETT. 388 211-216 (1996).
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| Documentation | The link module (also known as HABM (HA binding module) or PTR (proteoglycan
tandem repeat) is an approximately 100 amino acid long hyaluronic acid-
binding domain found in vertebrate proteins involved in assembling the
extracellular matrix and in cell adhesion and migration [1-3]. The structure
consists of two alpha-helices and two short anti-parallel beta-strands built
around a hydrophobic core [2]. The module contains four conserved cysteines
involved in two disulphide bridges, as illustrated schematically below:
+----------+
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xxxxCxxxxxxxxxxxCxxxxxxxxxxCxxxxxxxxxxxxxxxCxxxxx
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+--------------------------------------+
Proteins containing link modules include the proteoglycans aggrecan,
brevican, neurocan and versican, and the cartilage link protein, each of
which contain two modules; tumor necrosis factor-inducible protein TSG-6
and CD44 cell surface antigen, which each contain a single module (that in
CD44 being at the N-terminus).
LINKMODULE is a 4-element fingerprint that provides a signature for the
link module. The fingerprint was derived from an initial alignment of 5
sequences: the motifs were drawn from strategically selected conserved
regions spanning the full alignment length - motif 1 encodes the N-terminal
helical region and first conserved cysteine residue; motif 2 spans the
region flanking the second conserved Cys; motif 3 includes the region
preceding the third conserved Cys; and motif 4 is centred on the short
C-terminal beta-strand and fourth conserved Cys. Two iterations on
SPTR37_10f were required to reach convergence, at which point a true
set comprising 41 sequences was identified.
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