1SRA

STRUCTURE OF A NOVEL EXTRACELLULAR CA2+-BINDING MODULE IN BM-40(SLASH)SPARC(SLASH)OSTEONECTIN

Summary for 1SRA

• Entry DOI: 10.2210/pdb1sra/pdb
• Descriptor: SPARC, CALCIUM ION (3 entities in total)
• Functional Keywords: extracellular matrix protein, calcium-binding protein
• Biological source: Homo sapiens (human)
• Cellular location: Secreted, extracellular space, extracellular matrix, basement membrane: P09486
• Total number of polymer chains: 1
• Total formula weight: 18060.66

Authors

Hohenester, E.,Maurer, P.,Hohenadl, C.,Timpl, R.,Jansonius, J.N.,Engel, J. (deposition date: 1995-08-21, release date: 1996-03-08, Last modification date: 2024-11-20)

Primary citation

Hohenester, E.,Maurer, P.,Hohenadl, C.,Timpl, R.,Jansonius, J.N.,Engel, J.
Structure of a novel extracellular Ca(2+)-binding module in BM-40.
Nat.Struct.Biol., 3:67-73, 1996

PubMed Abstract: The EF-hand is a highly conserved Ca(2+)-binding motif found in many cytosolic Ca(2+)-modulated proteins. Here we report the crystal structure at 2.0 A resolution of the carboxy-terminal domain of human BM-40 (SPARC, osteonectin), an extracellular matrix protein containing an EF-hand pair. The two EF-hands interact canonically but their detailed structures are unusual. In the first EF-hand a one-residue insertion is accommodated by a cis-peptide bond and by substituting a carboxylate by a peptide carbonyl as a Ca2+ ligand. The second EF-hand is stabilized by a disulphide bond. The EF-hand pair interacts tightly with an amphiphilic amino-terminal helix, reminiscent of target peptide binding by calmodulin. The present structure defines a novel protein module occurring in several other extracellular proteins.

PubMed: 8548457
DOI: 10.1038/nsb0196-67

Experimental method

X-RAY DIFFRACTION (2 Å)