HIS-CbpA binds collagen types I, II, and IV but not fibronectin. Five micrograms of each protein was spotted onto nitrocellulose and incubated with 50 μg of HIS-CbpA per ml. The binding of HIS-CbpA was detected by immunostaining with anti-HIS-CbpA diluted 1/500. 1, BSA; 2, trypsin inhibitor; 3, bovine collagen type I; 4, bovine collagen type II; 5, murine collagen type IV, 6: bovine fibronectin. Immunostaining with preimmune serum diluted 1/500 resulted in no reactivity (data not shown).