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Bioinformatic analysis and molecular modelling of human ameloblastin suggest a two‐domain intrinsically unstructured calcium‐binding protein
Author(s) -
Vymětal Jiří,
Slabý Ivan,
Spahr Axel,
Vondrášek Jiří,
Lyngstadaas S. Petter
Publication year - 2008
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2008.00526.x
Subject(s) - ameloblast , intrinsically disordered proteins , computational biology , chemistry , structural similarity , calcium binding protein , function (biology) , microbiology and biotechnology , enamel paint , biology , calcium , biochemistry , materials science , composite material , organic chemistry
Ameloblastin (AMBN) was originally believed to be an enamel‐specific extracellular matrix glycoprotein secreted by ameloblasts. Recently, AMBN expression was also detected in developing mesenchymal dental hard tissues, in trauma‐induced reparative dentin, and during early craniofacial bone formation. The function and structure of AMBN still remain ambiguous, and there are no known proteins with similar primary sequences. We therefore performed a bio‐informatic analysis of AMBN to model ab initio the three‐dimensional structure of the molecule. The results suggest that AMBN is a two‐domain, intrinsically unstructured protein (IUP). The analysis did not reveal any regions with structural similarity to known receptor–ligand systems, and did not identify any higher‐order structures similar to functional regions in other known sequences. The AMBN model predicts 11 defined regions exposed on the surface, internalizing the rest of the molecule including a human‐specific insert. Molecular dynamics analysis identified one specific and several non‐specific calcium‐binding regions, mostly at the C‐terminal part of the molecule. The model is supported by previous observations that AMBN is a bipolar calcium‐binding molecule and hints at a possible role in protein–protein interactions. The model provides information useful for further studies on the function of AMBN.