A phage antibody to the active site of human placental alkaline phosphatase with higher affinity to the enzyme–substrate complex

A Streptomyces-specific member of the metallophosphatase superfamily contributes to spore dormancy and interaction with Aspergillus proliferans

We have identified, cloned and characterized a formerly unknown protein from Streptomyces lividans spores. The deduced protein belongs to a novel member of the metallophosphatase superfamily and contains a phosphatase domain and predicted binding sites for divalent ions. Very close relatives are encoded in the genomic DNA of many different Streptomyces species. As the deduced related homologues diverge from other known phosphatase types, we named the protein MptS (metallophosphatase type from Streptomyces). Comparative physiological and biochemical investigations and analyses by fluorescence microscopy of the progenitor strain, designed mutants carrying either a disruption of the mptS gene or the reintroduced gene as fusion with histidine codons or the egfp gene led to the following results: (i) the mptS gene is transcribed in the course of aerial mycelia formation. (ii) The MptS protein is produced during the late stages of growth, (iii) accumulates within spores, (iv) functions as an active enzyme that releases inorganic phosphate from an artificial model substrate, (v) is required for spore dormancy and (vi) MptS supports the interaction amongst Streptomyces lividans spores with conidia of the fungus Aspergillus proliferans. We discuss the possible role(s) of MptS-dependent enzymatic activity and the implications for spore biology.

Humanization of high affinity anti-HBs antibody by using human consensus sequence and modification of selected minimal positional template and packing residues

We had earlier reported the construction and characterization of a high affinity recombinant scFv generated from a potential neutralizing mouse monoclonal antibody against the Hepatitis B surface antigen. In this report we describe the humanization of this scFv by grafting its antigen binding site onto framework of the human consensus sequence of highest similarity. We have used molecular modeling to alter not only the clearly permissible residues but also several minimal positional template and V(H)/V(L) interface residues. The humanized scFv retains the binding characteristic of the mouse monoclonal even under conditions that usually destabilize antigen antibody interactions. This high affinity humanized scFv provides a basis for the development of prophylactic/therapeutic molecules.