8I74

Crystal structure of decarboxylated osteocalcin at pH 8.5

Summary for 8I74

• Entry DOI: 10.2210/pdb8i74/pdb
• Descriptor: Osteocalcin (2 entities in total)
• Functional Keywords: ca-binding protein, structural protein
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 2
• Total formula weight: 8495.23

Authors

Yokoyama, T.,Nabeshima, Y.,Obita, T.,Mizuguchi, M. (deposition date: 2023-01-31, release date: 2024-01-31, Last modification date: 2024-10-23)

Primary citation

Mizuguchi, M.,Yokoyama, T.,Otani, T.,Kuribara, S.,Nabeshima, Y.,Obita, T.,Hirata, M.,Kawano, K.
Structural and mutational analyses of decarboxylated osteocalcin provide insight into its adiponectin-inducing activity.
Febs Lett., 597:1479-1488, 2023

PubMed Abstract: An acidic environment in bone is essential for bone metabolism and the production of decarboxylated osteocalcin, which functions as a regulatory hormone of glucose metabolism. Here, we describe the high-resolution X-ray crystal structure of decarboxylated osteocalcin under acidic conditions. Decarboxylated osteocalcin at pH 2.0 retains the α-helix structure of native osteocalcin with three γ-carboxyglutamic acid residues at neutral pH. This implies that decarboxylated osteocalcin is stable under an acidic environment in bone. In addition, site-directed mutagenesis revealed that Glu17 and Glu21 are important for the adiponectin-inducing activity of decarboxylated osteocalcin. These findings suggest that the receptor of decarboxylated osteocalcin responds to the negative charge in helix 1 of osteocalcin.

PubMed: 36976525
DOI: 10.1002/1873-3468.14618

Experimental method

X-RAY DIFFRACTION (1.36 Å)