P159 is a proteolytically processed, surface adhesin ofMycoplasma hyopneumoniae: defined domains of P159 bind heparin and promote adherence to eukaryote cells

Summary Mycoplasma hyopneumoniae, the causative agent of porcine enzootic pneumonia, colonizes the respiratory cilia of affected swine causing significant economic losses to swine production worldwide. Heparin is known to inhibit adherence ofM. hyopneumoniaeto porcine respiratory epithelial cilia.M. hyopneumoniaecells bind heparin but the identity of the heparin‐binding proteins is limited. Proteomic analysis ofM. hyopneumoniaelysates identified 27 kDa (P27), 110 kDa (P110) and 52 kDa (P52) proteins representing different regions of a 159 kDa (P159) protein derived from mhp494. These cleavage fragments were surface located and present at all growth stages. Following purification of four recombinant proteins spanning P159 (F1P159, F2P159, F3P159and F4P159), only F3P159and F4P159bound heparin in a dose‐dependent manner (Kdvalues 142.37 ± 22.01 nM; 75.37 ± 7.34 nM respectively). Scanning electron microscopic studies showedM. hyopneumoniaebound intimately to porcine kidney epithelial‐like cells (PK15 cells) but these processes were inhibited by excess heparin and F4P159. Similarly, latex beads coated with F2P159and F4P159adhered to and entered PK15 cells, but heparin, F2P159and F4P159was inhibitory. These findings indicate that P159 is a post‐translationally cleaved, glycosaminoglycan‐binding adhesin ofM. hyopneumoniae.