Dimer conformation of soluble PECAM-1, an endothelial marker. (August 2016)

• Record Type: Journal Article
• Authors: Jiang, Longguang; Lin, Lin; Li, Rui; Yuan, Cai; Xu, Mingming; Huang, Joy H.; Huang, Mingdong
• Is Part Of: International journal of biochemistry & cell biology. Volume 77:Part A(2016:Aug.)
• Page Start: 102
• Page End: 108
• Publication Date: 2016-08
• Subjects: PECAM-1 -- Immunoglobulin domains -- Dimer -- Homophilic interactions -- SAXS; Biochemistry -- Periodicals; Cytology -- Periodicals; Biochemistry -- Periodicals; Cell Biology -- Periodicals; Biochimie -- Périodiques; Cytologie -- Périodiques; Biochimie; Cytologie; Biochemistry; Cytology; Ressource Internet (Descripteur de forme); Périodique électronique (Descripteur de forme); Periodicals; 572.05
• DOI: 10.1016/j.biocel.2016.06.001
• Languages: English
• ISSNs: 1357-2725

Abstract

Graphical abstract: Highlights: PECAM-1 is commonly-used as an endothelial cell marker. The structural details of homophilic interaction of sPECAM-1 are unknown. Recombinant sPECAM-1 in large quantity by Drosophila expression system. We observed the predominant presence of sPECAM-1 as a dimer on gel filtration chromatography and dynamic light scattering. Small-angle X-ray scattering reveals sPECAM-1 is a homophilic adhesion protein. sPECAM-1 formed a symmetric homodimer of Ω-shape in solution. The sPECAM-1 dimer is mediated through the intermolecular interactions through the first N-terminal domain of sPECAM-1 (D1). Abstract: Platelet endothelial cell adhesion molecule 1 (PECAM-1) is a cell surface receptor widely distributed on endothelium and hematopoietic-derived cells, and maintain the integrity of the blood vessels. PECAM-1 is widely recognized as an endothelial cell marker. The homophilic interaction through its extracellular domain of PECAM-1 (soluble PECAM-1, or sPECAM-1) is important to its functions. However, structural details for such dimerization are not fully understood. Here we report the production of recombinant sPECAM-1 in large quantity by Drosophila expression system and the small-angle X-ray diffraction (SAXS) study. The recombinant sPECAM-1 was found to form one population of dimer, but not oligomer, and was able to bind to heparin immobilized on a chip in surface plasmon resonance imaging (SPRi) binding experiments. The results of SAXS demonstrated that sPECAM-1 formed a symmetric homodimer of Ω-shape in solution, and each protomer adopted an extended conformation. The dimer is mediated through the intermolecular interactions through the first N-terminal domain (D1) of sPECAM-1. This model provides new structural information for its homophilic interaction mechanism.