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A bacterial collagen‐binding domain with novel calcium‐binding motif controls domain orientation
Author(s) -
Wilson Jeffrey J.,
Matsushita Osamu,
Okabe Akinobu,
Sakon Joshua
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg172
Subject(s) - linker , calcium , biophysics , binding domain , binding site , biochemistry , biology , collagenase , plasma protein binding , crystallography , chemistry , enzyme , organic chemistry , computer science , operating system
The crystal structure of a collagen‐binding domain (CBD) with an N‐terminal domain linker from Clostridium histolyticum class I collagenase was determined at 1.00 Å resolution in the absence of calcium (1NQJ) and at 1.65 Å resolution in the presence of calcium (1NQD). The mature enzyme is composed of four domains: a metalloprotease domain, a spacing domain and two CBDs. A 12‐residue‐long linker is found at the N‐terminus of each CBD. In the absence of calcium, the CBD reveals a β‐sheet sandwich fold with the linker adopting an α‐helix. The addition of calcium unwinds the linker and anchors it to the distal side of the sandwich as a new β‐strand. The conformational change of the linker upon calcium binding is confirmed by changes in the Stokes and hydrodynamic radii as measured by size exclusion chromatography and by dynamic light scattering with and without calcium. Furthermore, extensive mutagenesis of conserved surface residues and collagen‐binding studies allow us to identify the collagen‐binding surface of the protein and propose likely collagen–protein binding models.