Diversity of cell envelope proteinase specificity among strains of Lactococcus lactis and its relationship to charge characteristics of the substrate-binding region.

摘要: The biochemical and genetical diversity of the subtilisin-like cell envelope proteinase (CEP) among Lactococcus lactis strains was investigated. specificities proteinases 16 toward important cheese peptide alpha s1-casein fragment 1 to 23 two differently charged chromophoric peptides have been determined. On basis results, these could be classified into seven groups. contribution specificity specific residues in large C-terminal segment, which differentiates this from most other members subtilisin family, established with hybrid proteinases, even case small substrates. These remote substrate-binding region are therefore assumed spatially close each together constitute binding CEP. DNA sequence analysis fragments gene (prtP) encoding segments contain relevant shows that studied, is negatively CEP group represented by strain HP positively AM1 SK11. Consequently, groups show divergent specificities. Each a different intermediate part reflection an charge region. However, results suggest amino acid outside known CEP-binding also contribute specificity.(ABSTRACT TRUNCATED AT 250 WORDS)