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A highly efficient protein degradation system in Bacillus sp. CN2: a functional-degradomics study

  • 发表刊物: Applied Microbiology and Biotechnology
  • 关键字: Bacillussp. CN2, Proteins degradation, Functional-degradome, S8 serine endopeptidases, Multi-enzyme synergism
  • 论文类型: 期刊论文
  • 学科门类: 理学
  • 一级学科: 生物学
  • 文献类型: J
  • 卷号: 105
  • 期号: 2
  • 页面范围: 707-723
  • 是否译文:
  • 发表时间: 2021-05-01
  • 收录刊物: SCI
摘要: A novel protease-producing Bacillus sp. CN2 isolated from chicken manure composts exhibited a relatively high proteolytic specific activity. The strain CN2 degradome consisted of at least 149 proteases and homolog candidates, which were distributed into 4 aspartic, 30 cysteine, 55 metallo, 56 serine, and 4 threonine proteases. Extracellular proteolytic activity was almost completely inhibited by PMSF (phenylmethylsulfonyl fluoride) rather than o-P, E-64, or pepstatin A, suggesting that strain CN2 primarily secreted serine protease. More importantly, analysis of the extracellular proteome of strain CN2 revealed the presence of a highly efficient protein degradation system. Three serine proteases of the S8 family with different active site architectures firstly fragmented protein substrates which were then degraded to smaller peptides by a M4 metalloendopeptidase that prefers to degrade hydrophobic peptides and by a S13 carboxypeptidase. Those enzymes acted synergistically to degrade intact substrate proteins outside the cell. Furthermore, highly expressed sequence-specific intracellular aminopeptidases from multiple families (M20, M29, and M42) accurately degraded peptides into oligopeptides or amino acids, thus realizing the rapid acquisition and utilization of nitrogen sources. In this paper, a systematic study of the functional-degradome provided a new perspective for understanding the complexity of the protease hydrolysis system of Bacillus, and laid a solid foundation for further studying the precise degradation of proteins with the cooperative action of different family proteases.