Identification of a group of Haemophilus influenzae penicillin-binding proteins that may have complementary physiological roles

[35S]penicillin bound to different Haemophilus influenzae proteins in assays performed at 20, 37, or 42 degrees C. Penicillin-binding proteins 3a, 3b, 4, and 4' formed a group characterized by their affinity for moxalactam, cefotaxime, and piperacillin. Penicillin-binding protein 4' showed specific properties that may reflect its complementary role in septation.