A search to identify proteins with high affinity for @entity1877 -containing pneumococcal cell walls ( @entity1877 -binding proteins) has permitted the localization, cloning, sequencing, and overexpression of a gene (pce), coding for a protein (Pce) that liberates @entity2945 from purified cell walls of @entity328 . The pce gene of the pneumococcal strain R6 encodes a protein of 627 @entity1522 with a predicted Mr of 72,104. Pce can remove a maximum of 20% @entity2945 residues from the cell wall teichoic acid. In silico analysis of Pce shows a modular organization of the enzyme where the @entity1877 -binding domain, involved in cell wall substrate recognition, and the catalytic domain are located at the @entity1473 - and @entity1472 -terminal moieties of the protein, respectively. Remarkably, a long tail of 85 @entity1522 follows the @entity1473 -terminal domain, a structural feature that had not been described for the published @entity1877 -binding proteins. The @entity1473 -terminal moiety of Pce is assembled by 10 repeated motifs, and the protein has also a cleavable signal peptide of 25 @entity1522 that renders after its cleavage a mature protein of 69,426 Da (602 @entity1522 ). The pce gene has been expressed in @entity526 , and Pce was active when assayed on pneumococcal walls. We have also found that the signal peptide of Pce was functional in @entity526 . Biochemical analysis suggested that Pce is the teichoic acid @entity2945 esterase of @entity2260 that had been biochemically characterized previously. Construction of two pce pneumococcal mutants (R6D and @entity69708 ) by insertion-duplication mutagenesis revealed that these mutants grew at a doubling-time similar to those of the parental strains of the wild-type R6 and the lytA-mutant M31, respectively. R6D and @entity69708 were morphologically indistinguishable from the parental strains when whole-mounted cells were observed under the electron microscope and exhibited levels of competence for genetic transformation slightly lower than those reported for R6 and M31.

Molecular characterization of the pneumococcal teichoic acid XXXX esterase.

@entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity1472 :: ('CHEBI:46882', 'Chemical') :: ['amino'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli'] @entity2260 :: ('2104', 'Species') :: ['S. pneumoniae'] @entity1877 :: ('MESH:D002794', 'Chemical') :: ['choline'] @entity69708 :: ('p|SUB|M|31|D', 'ProteinMutation') :: ['M31D'] @entity2945 :: ('MESH:D010767', 'Chemical') :: ['phosphorylcholine'] @entity328 :: ('1313', 'Species') :: ['Streptococcus pneumoniae'] @entity1473 :: ('CHEBI:46883', 'Chemical') :: ['carboxy']
@entity2945 :: (MESH:D010767,Chemical) :: ['phosphorylcholine']
