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Effect of linker segments on the stability of epithelial cadherin domain 2
Author(s) -
Prasad Alka,
Zhao Huaying,
Rutherford John M.,
Housley Nicole,
Nichols Corey,
Pedigo Susan
Publication year - 2005
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20657
Subject(s) - linker , chemistry , biophysics , calcium , egf like domain , domain (mathematical analysis) , transmembrane protein , crystallography , extracellular , globular protein , stereochemistry , biochemistry , biology , binding domain , binding site , receptor , computer science , mathematics , organic chemistry , mathematical analysis , operating system
Epithelial cadherin is a transmembrane protein that is essential in calcium‐dependent cell–cell recognition and adhesion. It contains five independently folded globular domains in its extracellular region. Each domain has a seven‐strand β‐sheet immunoglobulin fold. Short seven‐residue peptide segments connect the globular domains and provide oxygens to chelate calcium ions at the interface between the domains (Nagar et al., Nature 1995;380:360–364). Recently, stability studies of ECAD2 (Prasad et al., Biochemistry 2004;43:8055–8066) were undertaken with the motivation that Domain 2 is a representative domain for this family of proteins. The definition of a domain boundary is somewhat arbitrary; hence, it was important to examine the effect of the adjoining linker regions that connect Domain 2 to the adjacent domains. Present studies employ temperature–denaturation and proteolytic susceptibility to provide insight into the impact of these linkers on Domain 2. The significant findings of our present study are threefold. First, the linker segments destabilize the core domain in the absence of calcium. Second, the destabilization due to addition of the linker segments can be partially reversed by the addition of calcium. Third, sodium chloride stabilizes all constructs. This result implies that electrostatic repulsion is a contributor to destabilization of the core domain by addition of the linkers. Thus, the context of Domain 2 within the whole molecule affects its thermodynamic characteristics. Proteins 2006. © 2005 Wiley‐Liss, Inc.