Related Experiment Video
Updated: Jun 19, 2026

From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
Bone recognition mechanism of porcine osteocalcin from crystal structure
Quyen Q Hoang1, Frank Sicheri, Andrew J Howard
1Department of Biochemistry, Faculty of Health Science, McMaster University, Hamilton, Ontario L8N 3Z5, Canada.
Abstract:
Osteocalcin is the most abundant noncollagenous protein in bone, and its concentration in serum is closely linked to bone metabolism and serves as a biological marker for the clinical assessment of bone disease. Although its precise mechanism of action is unclear, osteocalcin influences bone mineralization, in part through its ability to bind with high affinity to the mineral component of bone, hydroxyapatite. In addition to binding to hydroxyapatite, osteocalcin functions in cell signalling and the recruitment of osteoclasts and osteoblasts, which have active roles in bone resorption and deposition, respectively. Here we present the X-ray crystal structure of porcine osteocalcin at 2.0 A resolution, which reveals a negatively charged protein surface that coordinates five calcium ions in a spatial orientation that is complementary to calcium ions in a hydroxyapatite crystal lattice. On the basis of our findings, we propose a model of osteocalcin binding to hydroxyapatite and draw parallels with other proteins that engage crystal lattices.
Related Concept Videos
Bone Structure
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Globular and Fibrous Proteins
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Protein Organization
The primary structure of a protein is its amino acid sequence.
The Bone Matrix
Compact Bone
Compact bone, also called cortical bone, is the denser, stronger of the two types of bone tissue. It is found under the periosteum and in the diaphyses of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon, or haversian system. Each osteon is composed of concentric rings of calcified...

