A working structural model of penicillin-binding protein 1B (PBP 1B) from Escherichia coli derived from previous data consists of a highly charged amino-terminal cytoplasmic tail, a 23-amino-acid hydrophobic transmembrane anchor, and a 758-amino-acid periplasmic domain. Using an engineered thrombin cleavage site, we have investigated the solubility properties of the periplasmic domain of PBP 1B. Twelve amino acids, comprised of the consensus thrombin cleavage site (LVPR↓GS) and flanking glycine residues, were inserted into PBP 1B just past its putative transmembrane segment. To aid in purification, a hexahistidine tag was also inserted at its amino terminus, and the engineered protein (PBP 1B-GT/H6) was purified and characterized.A working structural model of penicillin-binding protein 1B (PBP 1B) from Escherichia coli derived from previous data consists of a highly charged amino-terminal cytoplasmic tail, a 23-amino-acid hydrophobic transmembrane anchor, and a 758-amino-acid periplasmic domain. Using an engineered thrombin cleavage site, we have investigated the solubility properties of the periplasmic domain of PBP 1B. Twelve amino acids, comprised of the consensus thrombin cleavage site (LVPR↓GS) and flanking glycine residues, were inserted into PBP 1B just past its putative transmembrane segment. To aid in purification, a hexahistidine tag was also inserted at its amino terminus, and the engineered protein (PBP 1B-GT/H6) was purified and characterized
